Searched hist:e66f91a2 (Results 1 – 2 of 2) sorted by relevance
| /openbmc/linux/drivers/soundwire/ |
| H A D | intel_auxdevice.c | e66f91a2 Mon Jul 31 04:13:33 CDT 2023 Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> soundwire: intel_auxdevice: add hybrid IDA-based device_number allocation
The IDA-based allocation is useful to simplify debug, but it was also
introduced as a prerequisite to deal with the Intel Lunar Lake
hardware programming sequences: the wake-ups have to be handled with a
system-unique SDI address at the HDaudio controller level.
At the time, the restriction introduced by the IDA to 8 devices total
seemed perfectly fine, but recently hardware vendors created
configurations with more than 8 devices.
Add a new allocation strategy to allow for more than 8 devices using
information on the type of devices, and only use the IDA-based
allocation for devices capable of generating a wake.
In theory the information on wake capabilities should come from
firmware, but none of the existing ACPI tables provide it. The drivers
set the 'wake_capable' property, but this cannot be used reliably: if
the driver probe happens *after* the enumeration, then that property
is not initialized yet. Trying to modify the device_number on-the-fly
proved to be an impossible task generating race conditions left and
right.
The only reliable work-around to control the enumeration is to add a
quirk table. It's ugly but until platform firmware improves, hopefully as a
result of MIPI/SDCA stardization, we can expect that quirk table to
grow for each new headset or microphone codec.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20230731091333.3593132-4-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
|
| /openbmc/linux/include/linux/soundwire/ |
| H A D | sdw_intel.h | e66f91a2 Mon Jul 31 04:13:33 CDT 2023 Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> soundwire: intel_auxdevice: add hybrid IDA-based device_number allocation
The IDA-based allocation is useful to simplify debug, but it was also
introduced as a prerequisite to deal with the Intel Lunar Lake
hardware programming sequences: the wake-ups have to be handled with a
system-unique SDI address at the HDaudio controller level.
At the time, the restriction introduced by the IDA to 8 devices total
seemed perfectly fine, but recently hardware vendors created
configurations with more than 8 devices.
Add a new allocation strategy to allow for more than 8 devices using
information on the type of devices, and only use the IDA-based
allocation for devices capable of generating a wake.
In theory the information on wake capabilities should come from
firmware, but none of the existing ACPI tables provide it. The drivers
set the 'wake_capable' property, but this cannot be used reliably: if
the driver probe happens *after* the enumeration, then that property
is not initialized yet. Trying to modify the device_number on-the-fly
proved to be an impossible task generating race conditions left and
right.
The only reliable work-around to control the enumeration is to add a
quirk table. It's ugly but until platform firmware improves, hopefully as a
result of MIPI/SDCA stardization, we can expect that quirk table to
grow for each new headset or microphone codec.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20230731091333.3593132-4-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
|