From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: alsa-devel@alsa-project.org, tiwai@suse.de,
linux-kernel@vger.kernel.org,
Ranjani Sridharan <ranjani.sridharan@linux.intel.com>,
vkoul@kernel.org, broonie@kernel.org,
srinivas.kandagatla@linaro.org, jank@cadence.com,
slawomir.blauciak@intel.com,
Bard liao <yung-chuan.liao@linux.intel.com>,
Rander Wang <rander.wang@linux.intel.com>
Subject: Re: [alsa-devel] [RFC PATCH 0/2] soundwire: add master_device/driver support
Date: Fri, 14 Feb 2020 17:34:40 -0600 [thread overview]
Message-ID: <0ec41a5b-6132-6940-f1b3-bac1724b70a4@linux.intel.com> (raw)
In-Reply-To: <20200214164919.GB4016987@kroah.com>
On 2/14/20 10:49 AM, Greg KH wrote:
> On Fri, Jan 31, 2020 at 10:20:09PM -0600, Pierre-Louis Bossart wrote:
>> The SoundWire master representation needs to evolve to take into account:
>>
>> a) a May 2019 recommendation from Greg KH to remove platform devices
>>
>> b) the need on Intel platforms to support hardware startup only once
>> the power rail dependencies are settled. The SoundWire master is not
>> an independent IP at all.
>>
>> c) the need to deal with external wakes handled by the PCI subsystem
>> in specific low-power modes
>>
>> In case it wasn't clear, the SoundWire subsystem is currently unusable
>> with v5.5 on devices hitting the shelves very soon (race conditions,
>> power management, suspend/resume, etc). v5.6 will only provide
>> interface changes and no functional improvement. We've circled on the
>> same concepts since September 2019, and I hope this direction is now
>> aligned with the suggestions from Vinod Koul and that we can target
>> v5.7 as the 'SoundWire just works(tm)' version.
>>
>> This series is provided as an RFC since it depends on patches already
>> for review.
>
> Both of these look sane to me, nice work!
>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Thanks Greg, I really appreciate the review and educational guidance on
the use of platform devices!
If that's alright with Vinod and you, I'd like to defer the integration
of these patches a bit so that we can improve them a bit e.g.
- I realized earlier this week there's a potential issue with the
'shutdown' callback, what I did looks duplicated with 'shutdown' called
from the device core and by the parent.
- it would make sense to add support for this 'master device' in the
Qualcomm drivers as well, so that we are aligned with a similar device
hierarchy (PCI -> sdw_master_device and DT/plaforms ->sdw_master_device).
- we probably want to add the sysfs patches that started this discussion
on the platform devices. This would be very useful to debug new
platforms, we depend on BIOS/firmware and we can't always know the
actual settings just by looking at the DSDT static contents (multiple
tests and overridden values).
My preference in terms of integration in drivers/soundwire would be
1. Intel DAI cleanup (only one kfree missing, will resubmit v3 today)
2. [PATCH 00/10] soundwire: bus: fix race conditions, add suspend-resume
this series solves a lot of issues and should go first.
3. ASoC/SOF integration (still with platform devices)
I narrowed this down to 6 patches, that would help me submit the rest of
the ASoC/SOF patches in Mark Brown's tree. That would be Intel specific.
This step would be the first where everything SoundWire-related can be
enabled in a build, and while we've caught a lot of cross-compilation
issues it's likely some bots will find corner cases to keep us busy.
4. master_device/driver transition: these updated patches removing
platform devices + sysfs support + Qualcomm support (the last point
would depend on the workload/support of Qualcomm/Linaro folks, I don't
want to commit on their behalf).
5. New SoundWire functionality for Intel platforms (clock-stop/restart
and synchronized links). The code would be only located in
drivers/soundwire and be easier to handle. For the synchronized links we
still have a bit of validation work to do so it should really come last.
Would this work for everyone?
Thanks,
-Pierre
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next prev parent reply other threads:[~2020-02-14 23:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-01 4:20 [alsa-devel] [RFC PATCH 0/2] soundwire: add master_device/driver support Pierre-Louis Bossart
2020-02-01 4:20 ` [alsa-devel] [RFC PATCH 1/2] soundwire: bus_type: " Pierre-Louis Bossart
2020-02-01 4:20 ` [alsa-devel] [RFC PATCH 2/2] soundwire: intel: transition to sdw_master_device/driver support Pierre-Louis Bossart
2020-02-14 16:49 ` [alsa-devel] [RFC PATCH 0/2] soundwire: add master_device/driver support Greg KH
2020-02-14 23:34 ` Pierre-Louis Bossart [this message]
2020-02-15 0:05 ` Greg KH
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