drm/radeon: Only build fbdev if DRM_FBDEV_EMULATION is set

Make building fbdev emulation depend on DRM_FBDEV_EMULATION. Also
rename the source file to radeon_fbdev.c to align with other fbdev
files.

drm/radeon: Only build fbdev if DRM_FBDEV_EMULATION is set

Make building fbdev emulation depend on DRM_FBDEV_EMULATION. Also
rename the source file to radeon_fbdev.c to align with other fbdev
files.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm/radeon: Implement client-based fbdev emulation

Implement fbdev emulation on top of struct drm_client and its helpers.
Replaces ad-hoc interfaces for restoring and closing fbdev emulation with
pe

drm/radeon: Implement client-based fbdev emulation

Implement fbdev emulation on top of struct drm_client and its helpers.
Replaces ad-hoc interfaces for restoring and closing fbdev emulation with
per-client callbacks for hotplugging, restoring and unregistering.

A single function, radeon_fbdev_setup(), starts fbdev emulation after
the DRM device has been registered. Hence, fbdev acts like a regular
DRM client.

The setup call prepares the fbdev emulation and invokes connector
hotplugging. The first successful hotplug event initializes fbdev
emulation with a framebuffer, device file, etc.

Unregistering depends on the hotplug status. Fully initialized emulation
is cleaned up through drm_fb_helper_unregister_info() and fb_destroy.
For prepared-only setups, unregistering unprepares the emulation and
releases all resources. In both cases, fbdev emulation will be cleaned
up.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm/radeon: Remove struct radeon_fbdev

Both data fields in struct radeon_fbdev, the framebuffer and the
device, are already available in struct drm_fb_helper. Simplify
radeon by converting all calle

drm/radeon: Remove struct radeon_fbdev

Both data fields in struct radeon_fbdev, the framebuffer and the
device, are already available in struct drm_fb_helper. Simplify
radeon by converting all callers and removing struct radeon_fbdev.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm/radeon: Move radeon_align_pitch() next to dumb-buffer helpers

Move radeon_align_pitch() next to its caller in the dumb-buffer
code. Removes the only dependency on the radeon's fbdev source file

drm/radeon: Move radeon_align_pitch() next to dumb-buffer helpers

Move radeon_align_pitch() next to its caller in the dumb-buffer
code. Removes the only dependency on the radeon's fbdev source file
that is not related to fbdev emulation. No functional changes.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm/radeon: Remove unnecessary include statements for drm_crtc_helper.h

Several source files include drm_crtc_helper.h without needing it or
only to get its transitive include statements; leading to

drm/radeon: Remove unnecessary include statements for drm_crtc_helper.h

Several source files include drm_crtc_helper.h without needing it or
only to get its transitive include statements; leading to unnecessary
compile-time dependencies.

Directly include required headers and drop drm_crtc_helper.h where
possible.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230116131235.18917-15-tzimmermann@suse.de

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drm/radeon: remove unused declarations for radeon

radeon_combios_get_ext_tmds_info() has been removed since
commit fcec570b27a4 ("drm/radeon/kms: add support for
external tmds on legacy boards").

r

drm/radeon: remove unused declarations for radeon

radeon_combios_get_ext_tmds_info() has been removed since
commit fcec570b27a4 ("drm/radeon/kms: add support for
external tmds on legacy boards").

radeon_mst has been removed since
commit 01ad1d9c2888 ("drm/radeon: Drop legacy MST support").

r600_hdmi_acr() has been removed since
commit 64424d6e45ae ("radeon/audio: consolidate update_acr()
functions (v2)").

So remove the declarations for them from header file.

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220913024847.552254-4-cuigaosheng1@huawei.com

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drm/radeon: Drop legacy MST support

Right now, radeon is technically the only non-atomic driver still making
use of the MST helpers - and thus the final user of all of the legacy MST
helpers. Origin

drm/radeon: Drop legacy MST support

Right now, radeon is technically the only non-atomic driver still making
use of the MST helpers - and thus the final user of all of the legacy MST
helpers. Originally I was going to look into seeing if we could move legacy
MST into the radeon driver itself, however:

* SI and CIK both can use amdgpu, which still supports MST
* It currently doesn't work according to my own testing. I'm sure with some
troubleshooting we could likely fix it, but that brings me to point #2:
* It was never actually enabled by default, and is still marked as
experimental in the module parameter description
* If people were using it, someone probably would have probably seen a bug
report about how it is currently not functional by now. That certainly
doesn't appear to be the case, since before getting access to my own
hardware I had to go out of my way to try finding someone to help test
whether this legacy MST code even works - even amongst AMD employees.
* Getting rid of this code and only having atomic versions of the MST
helpers to maintain is likely going to be a lot easier in the long run,
and will make it a lot easier for others contributing to this code to
follow along with what's happening.

FWIW - if anyone still wants this code to be in the tree and has a good
idea of how to support this without needing to maintain the legacy MST
helpers (trying to move them would probably be acceptable), I'm happy to
suggestions. But my hope is that we can just drop this code and forget
about it. I've already run this idea by Harry Wentland and Alex Deucher a
few times as well.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-17-lyude@redhat.com

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drm/radeon: Drop CONFIG_BACKLIGHT_CLASS_DEVICE ifdefs

The DRM_RADEON Kconfig code contains:

select BACKLIGHT_CLASS_DEVICE

So the condition these ifdefs test for is always true, drop them.

Signed

drm/radeon: Drop CONFIG_BACKLIGHT_CLASS_DEVICE ifdefs

The DRM_RADEON Kconfig code contains:

select BACKLIGHT_CLASS_DEVICE

So the condition these ifdefs test for is always true, drop them.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm: Rename dp/ to display/

Rename dp/ to display/ to account for additional display-related
helpers, such as HDMI. Update all related include statements. No
functional changes.

Various drivers, su

drm: Rename dp/ to display/

Rename dp/ to display/ to account for additional display-related
helpers, such as HDMI. Update all related include statements. No
functional changes.

Various drivers, such as i915 and amdgpu, use similar naming scheme
by putting code for video-output standards into a local display/
directory. The new directory's name is aligned with this convention.

v2:
* update commit message (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220421073108.19226-3-tzimmermann@suse.de

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drm/dp: Move public DisplayPort headers into dp/

Move all public DisplayPort headers into dp/ and update users. No
functional changes.

v3:
* rebased onto latest drm-tip

Signed-off-by: Thomas Zimm

drm/dp: Move public DisplayPort headers into dp/

Move all public DisplayPort headers into dp/ and update users. No
functional changes.

v3:
* rebased onto latest drm-tip

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220114114535.29157-5-tzimmermann@suse.de

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drm/radeon: do not use drm middle layer for debugfs (v2)

Use debugfs API directly instead of drm middle layer.

v2: squash in build fix (Alex)

Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
Acked-b

drm/radeon: do not use drm middle layer for debugfs (v2)

Use debugfs API directly instead of drm middle layer.

v2: squash in build fix (Alex)

Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm/radeon: remove radeon_fb_{add,remove}_connector functions

drm_fb_helper_{add,remove}_one_connector() are dummy functions now
and serve no purpose. Hence remove their calls.

This is the preparat

drm/radeon: remove radeon_fb_{add,remove}_connector functions

drm_fb_helper_{add,remove}_one_connector() are dummy functions now
and serve no purpose. Hence remove their calls.

This is the preparatory step for removing the
drm_fb_helper_{add,remove}_one_connector() functions from
drm_fb_helper.h

Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200305120434.111091-3-pankaj.laxminarayan.bharadiya@intel.com

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drm/radeon: Convert to struct drm_crtc_helper_funcs.get_scanout_position()

The callback struct drm_driver.get_scanout_position() is deprecated in
favor of struct drm_crtc_helper_funcs.get_scanout_po

drm/radeon: Convert to struct drm_crtc_helper_funcs.get_scanout_position()

The callback struct drm_driver.get_scanout_position() is deprecated in
favor of struct drm_crtc_helper_funcs.get_scanout_position(). Convert
radeon over.

v4:
* 80-character line fixes

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200123135943.24140-11-tzimmermann@suse.de

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radeon: completely remove lut leftovers

This is an oversight from

commit 42585395ebc1034a98937702849669f17eadb35f
Author: Peter Rosin <peda@axentia.se>
Date: Thu Jul 13 18:25:36 2017 +0200

d

radeon: completely remove lut leftovers

This is an oversight from

commit 42585395ebc1034a98937702849669f17eadb35f
Author: Peter Rosin <peda@axentia.se>
Date: Thu Jul 13 18:25:36 2017 +0200

drm: radeon: remove dead code and pointless local lut storage

v2: Also remove leftover local variable.

Cc: Peter Rosin <peda@axentia.se>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm/radeon: radeon_framebuffer -> drm_framebuffer

Since drm_framebuffer can now store GEM objects directly, place them
there rather than in our own subclass. As this makes the framebuffer
create_han

drm/radeon: radeon_framebuffer -> drm_framebuffer

Since drm_framebuffer can now store GEM objects directly, place them
there rather than in our own subclass. As this makes the framebuffer
create_handle and destroy functions the same as the GEM framebuffer
helper, we can reuse those.

Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Stone <daniels@collabora.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: David (ChunMing) Zhou <David1.Zhou@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm/radeon: Move GEM BO to drm_framebuffer

Since drm_framebuffer can now store GEM objects directly, place them
there rather than in our own subclass. As this makes the framebuffer
create_handle and

drm/radeon: Move GEM BO to drm_framebuffer

Since drm_framebuffer can now store GEM objects directly, place them
there rather than in our own subclass. As this makes the framebuffer
create_handle and destroy functions the same as the GEM framebuffer
helper, we can reuse those.

Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Stone <daniels@collabora.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: David (ChunMing) Zhou <David1.Zhou@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm/radeon: Use drm_fb_helper_lastclose() and _poll_changed()

This driver can use drm_fb_helper_lastclose() in its .lastclose function.
It can also use drm_fb_helper_output_poll_changed() as its
.ou

drm/radeon: Use drm_fb_helper_lastclose() and _poll_changed()

This driver can use drm_fb_helper_lastclose() in its .lastclose function.
It can also use drm_fb_helper_output_poll_changed() as its
.output_poll_changed callback.

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm/radeon/dp: make radeon_dp_get_dp_link_config static

It's not used outside this file any longer.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.de

drm/radeon/dp: make radeon_dp_get_dp_link_config static

It's not used outside this file any longer.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm: radeon: remove dead code and pointless local lut storage

The redundant fb helpers .load_lut, .gamma_set and .gamma_get are
no longer used. Remove the dead code and hook up the crtc .gamma_set
t

drm: radeon: remove dead code and pointless local lut storage

The redundant fb helpers .load_lut, .gamma_set and .gamma_get are
no longer used. Remove the dead code and hook up the crtc .gamma_set
to use the crtc gamma_store directly instead of duplicating that
info locally.

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Peter Rosin <peda@axentia.se>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20170713162538.22788-13-peda@axentia.se

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drm/vblank: drop the mode argument from drm_calc_vbltimestamp_from_scanoutpos

If we restrict this helper to only kms drivers (which is the case) we
can look up the correct mode easily ourselves. But

drm/vblank: drop the mode argument from drm_calc_vbltimestamp_from_scanoutpos

If we restrict this helper to only kms drivers (which is the case) we
can look up the correct mode easily ourselves. But it's a bit tricky:

- All legacy drivers look at crtc->hwmode. But that is updated already
at the beginning of the modeset helper, which means when we disable
a pipe. Hence the final timestamps might be a bit off. But since
this is an existing bug I'm not going to change it, but just try to
be bug-for-bug compatible with the current code. This only applies
to radeon&amdgpu.

- i915 tries to get it perfect by updating crtc->hwmode when the pipe
is off (i.e. vblank->enabled = false).

- All other atomic drivers look at crtc->state->adjusted_mode. Those
that look at state->requested_mode simply don't adjust their mode,
so it's the same. That has two problems: Accessing crtc->state from
interrupt handling code is unsafe, and it's updated before we shut
down the pipe. For nonblocking modesets it's even worse.

For atomic drivers try to implement what i915 does. To do that we add
a new hwmode field to the vblank structure, and update it from
drm_calc_timestamping_constants(). For atomic drivers that's called
from the right spot by the helper library already, so all fine. But
for safety let's enforce that.

For legacy driver this function is only called at the end (oh the
fun), which is broken, so again let's not bother and just stay
bug-for-bug compatible.

The benefit is that we can use drm_calc_vbltimestamp_from_scanoutpos
directly to implement ->get_vblank_timestamp in every driver, deleting
a lot of code.

v2: Completely new approach, trying to mimick the i915 solution.

v3: Fixup kerneldoc.

v4: Drop the WARN_ON to check that the vblank is off, atomic helpers
currently unconditionally call this. Recomputing the same stuff should
be harmless.

v5: Fix typos and move misplaced hunks to the right patches (Neil).

v6: Undo hunk movement (kbuild).

Cc: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Cc: Eric Anholt <eric@anholt.net>
Cc: Rob Clark <robdclark@gmail.com>
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170509140329.24114-4-daniel.vetter@ffwll.ch

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drm: Don't include <drm/drm_encoder.h> in <drm/drm_crtc.h>

<drm/drm_crtc.h> used to define most of the in-kernel KMS API. It has
now been split into separate files for each object type, but still
in

drm: Don't include <drm/drm_encoder.h> in <drm/drm_crtc.h>

<drm/drm_crtc.h> used to define most of the in-kernel KMS API. It has
now been split into separate files for each object type, but still
includes most other KMS headers to avoid breaking driver compilation.

As a step towards fixing that problem, remove the inclusion of
<drm/drm_encoder.h> from <drm/drm_crtc.h> and include it instead where
appropriate. Also remove the forward declarations of the drm_encoder and
drm_encoder_helper_funcs structures from <drm/drm_crtc.h> as they're not
needed in the header.

<drm/drm_encoder.h> now has to include <drm/drm_mode.h> and contain a
forward declaration of struct drm_encoder in order to allow including it
as the first header in a compilation unit.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sinclair Yeh <syeh@vmware.com> # For vmwgfx
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1481709550-29226-2-git-send-email-laurent.pinchart+renesas@ideasonboard.com

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drm/radeon: Hide the HW cursor while it's out of bounds

Fixes hangs in that case under some circumstances.

v2:
* Only use non-0 x/yorigin if the cursor is (partially) outside of the
top/left edge

drm/radeon: Hide the HW cursor while it's out of bounds

Fixes hangs in that case under some circumstances.

v2:
* Only use non-0 x/yorigin if the cursor is (partially) outside of the
top/left edge of the total surface with AVIVO/DCE

Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1000433
Cc: stable@vger.kernel.org
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com> (v1)
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm/radeon: fix dp link rate selection (v2)

Need to properly handle the max link rate in the dpcd.
This prevents some cases where 5.4 Ghz is selected when
it shouldn't be.

v2: simplify logic, add a

drm/radeon: fix dp link rate selection (v2)

Need to properly handle the max link rate in the dpcd.
This prevents some cases where 5.4 Ghz is selected when
it shouldn't be.

v2: simplify logic, add array bounds check

Reviewed-by: Tom St Denis <tom.stdenis@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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drm/radeon: Fixup hw vblank counter/ts for new drm_update_vblank_count() (v2)

commit 4dfd6486 "drm: Use vblank timestamps to guesstimate how many
vblanks were missed" introduced in Linux 4.4-rc1 mak

drm/radeon: Fixup hw vblank counter/ts for new drm_update_vblank_count() (v2)

commit 4dfd6486 "drm: Use vblank timestamps to guesstimate how many
vblanks were missed" introduced in Linux 4.4-rc1 makes the drm core
more fragile to drivers which don't update hw vblank counters and
vblank timestamps in sync with firing of the vblank irq and
essentially at leading edge of vblank.

This exposed a problem with radeon-kms/amdgpu-kms which do not
satisfy above requirements:

The vblank irq fires a few scanlines before start of vblank, but
programmed pageflips complete at start of vblank and
vblank timestamps update at start of vblank, whereas the
hw vblank counter increments only later, at start of vsync.

This leads to problems like off by one errors for vblank counter
updates, vblank counters apparently going backwards or vblank
timestamps apparently having time going backwards. The net result
is stuttering of graphics in games, or little hangs, as well as
total failure of timing sensitive applications.

See bug #93147 for an example of the regression on Linux 4.4-rc:

https://bugs.freedesktop.org/show_bug.cgi?id=93147

This patch tries to align all above events better from the
viewpoint of the drm core / of external callers to fix the problem:

1. The apparent start of vblank is shifted a few scanlines earlier,
so the vblank irq now always happens after start of this extended
vblank interval and thereby drm_update_vblank_count() always samples
the updated vblank count and timestamp of the new vblank interval.

To achieve this, the reporting of scanout positions by
radeon_get_crtc_scanoutpos() now operates as if the vblank starts
radeon_crtc->lb_vblank_lead_lines before the real start of the hw
vblank interval. This means that the vblank timestamps which are based
on these scanout positions will now update at this earlier start of
vblank.

2. The driver->get_vblank_counter() function will bump the returned
vblank count as read from the hw by +1 if the query happens after
the shifted earlier start of the vblank, but before the real hw increment
at start of vsync, so the counter appears to increment at start of vblank
in sync with the timestamp update.

3. Calls from vblank irq-context and regular non-irq calls are now
treated identical, always simulating the shifted vblank start, to
avoid inconsistent results for queries happening from vblank irq vs.
happening from drm_vblank_enable() or vblank_disable_fn().

4. The radeon_flip_work_func will delay mmio programming a pageflip until
the start of the real vblank iff it happens to execute inside the shifted
earlier start of the vblank, so pageflips now also appear to execute at
start of the shifted vblank, in sync with vblank counter and timestamp
updates. This to avoid some races between updates of vblank count and
timestamps that are used for swap scheduling and pageflip execution which
could cause pageflips to execute before the scheduled target vblank.

The lb_vblank_lead_lines "fudge" value is calculated as the size of
the display controllers line buffer in scanlines for the given video
mode: Vblank irq's are triggered by the line buffer logic when the line
buffer refill for a video frame ends, ie. when the line buffer source read
position enters the hw vblank. This means that a vblank irq could fire at
most as many scanlines before the current reported scanout position of the
crtc timing generator as the number of scanlines the line buffer can
maximally hold for a given video mode.

This patch has been successfully tested on a RV730 card with DCE-3 display
engine and on a evergreen card with DCE-4 display engine, in single-display
and dual-display configuration, with different video modes.

A similar patch is needed for amdgpu-kms to fix the same problem.

Limitations:

- Line buffer sizes in pixels are hard-coded on < DCE-4 to a value
i just guessed to be high enough to work ok, lacking info on the true
sizes atm.

Fixes: fdo#93147

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Michel Dänzer <michel.daenzer@amd.com>
Cc: Harry Wentland <Harry.Wentland@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>

(v1) Tested-by: Dave Witbrodt <dawitbro@sbcglobal.net>

(v2) Refine radeon_flip_work_func() for better efficiency:

In radeon_flip_work_func, replace the busy waiting udelay(5)
with event lock held by a more performance and energy efficient
usleep_range() until at least predicted true start of hw vblank,
with some slack for scheduler happiness. Release the event lock
during waits to not delay other outputs in doing their stuff, as
the waiting can last up to 200 usecs in some cases.

Retested on DCE-3 and DCE-4 to verify it still works nicely.

(v2) Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

show more ...

drm/radeon: Fixup hw vblank counter/ts for new drm_update_vblank_count() (v2)

commit 4dfd6486 "drm: Use vblank timestamps to guesstimate how many
vblanks were missed" introduced in Linux 4.4-rc1 mak

drm/radeon: Fixup hw vblank counter/ts for new drm_update_vblank_count() (v2)

commit 4dfd6486 "drm: Use vblank timestamps to guesstimate how many
vblanks were missed" introduced in Linux 4.4-rc1 makes the drm core
more fragile to drivers which don't update hw vblank counters and
vblank timestamps in sync with firing of the vblank irq and
essentially at leading edge of vblank.

This exposed a problem with radeon-kms/amdgpu-kms which do not
satisfy above requirements:

The vblank irq fires a few scanlines before start of vblank, but
programmed pageflips complete at start of vblank and
vblank timestamps update at start of vblank, whereas the
hw vblank counter increments only later, at start of vsync.

This leads to problems like off by one errors for vblank counter
updates, vblank counters apparently going backwards or vblank
timestamps apparently having time going backwards. The net result
is stuttering of graphics in games, or little hangs, as well as
total failure of timing sensitive applications.

See bug #93147 for an example of the regression on Linux 4.4-rc:

https://bugs.freedesktop.org/show_bug.cgi?id=93147

This patch tries to align all above events better from the
viewpoint of the drm core / of external callers to fix the problem:

1. The apparent start of vblank is shifted a few scanlines earlier,
so the vblank irq now always happens after start of this extended
vblank interval and thereby drm_update_vblank_count() always samples
the updated vblank count and timestamp of the new vblank interval.

To achieve this, the reporting of scanout positions by
radeon_get_crtc_scanoutpos() now operates as if the vblank starts
radeon_crtc->lb_vblank_lead_lines before the real start of the hw
vblank interval. This means that the vblank timestamps which are based
on these scanout positions will now update at this earlier start of
vblank.

2. The driver->get_vblank_counter() function will bump the returned
vblank count as read from the hw by +1 if the query happens after
the shifted earlier start of the vblank, but before the real hw increment
at start of vsync, so the counter appears to increment at start of vblank
in sync with the timestamp update.

3. Calls from vblank irq-context and regular non-irq calls are now
treated identical, always simulating the shifted vblank start, to
avoid inconsistent results for queries happening from vblank irq vs.
happening from drm_vblank_enable() or vblank_disable_fn().

4. The radeon_flip_work_func will delay mmio programming a pageflip until
the start of the real vblank iff it happens to execute inside the shifted
earlier start of the vblank, so pageflips now also appear to execute at
start of the shifted vblank, in sync with vblank counter and timestamp
updates. This to avoid some races between updates of vblank count and
timestamps that are used for swap scheduling and pageflip execution which
could cause pageflips to execute before the scheduled target vblank.

The lb_vblank_lead_lines "fudge" value is calculated as the size of
the display controllers line buffer in scanlines for the given video
mode: Vblank irq's are triggered by the line buffer logic when the line
buffer refill for a video frame ends, ie. when the line buffer source read
position enters the hw vblank. This means that a vblank irq could fire at
most as many scanlines before the current reported scanout position of the
crtc timing generator as the number of scanlines the line buffer can
maximally hold for a given video mode.

This patch has been successfully tested on a RV730 card with DCE-3 display
engine and on a evergreen card with DCE-4 display engine, in single-display
and dual-display configuration, with different video modes.

A similar patch is needed for amdgpu-kms to fix the same problem.

Limitations:

- Line buffer sizes in pixels are hard-coded on < DCE-4 to a value
i just guessed to be high enough to work ok, lacking info on the true
sizes atm.

Fixes: fdo#93147

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Michel Dänzer <michel.daenzer@amd.com>
Cc: Harry Wentland <Harry.Wentland@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>

(v1) Tested-by: Dave Witbrodt <dawitbro@sbcglobal.net>

(v2) Refine radeon_flip_work_func() for better efficiency:

In radeon_flip_work_func, replace the busy waiting udelay(5)
with event lock held by a more performance and energy efficient
usleep_range() until at least predicted true start of hw vblank,
with some slack for scheduler happiness. Release the event lock
during waits to not delay other outputs in doing their stuff, as
the waiting can last up to 200 usecs in some cases.

Retested on DCE-3 and DCE-4 to verify it still works nicely.

(v2) Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

show more ...