[alsa-devel] 答复: 答复: 答复: [PATCH] vgaswitchroo: set audio client id according to bound gpu client id

Takashi Iwai tiwai at suse.de
Tue Jul 10 11:50:57 CEST 2018 

On Tue, 10 Jul 2018 11:13:27 +0200,
jimqu wrote:
> 
> 
> 
> On 2018年07月10日 16:01, Takashi Iwai wrote:
> > On Tue, 10 Jul 2018 09:44:42 +0200,
> > Qu, Jim wrote:
> >> Hi Takashi,
> >>
> >> I am not expert in audio driver, so I just update some test result, please help triage the issue.
> >>
> >> With audio runtime pm:
> > What does this mean?  Is it the stock 4.17.x (or 4.18-rc)?
> > Please clarify your test environment at first: which kernel, which
> > hardware setup.
> >
> This is v4.15 which backport Lukas' patches and also one bug fix
> https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git/commit/?id=57cb54e53bdd.
> The platform is AMDAPU(with audio) + AMD dGPU , it is a hybird GFX
> platform. In generic, dGPU will always be suspended.

Ah, so it's AMD+AMD, not Intel+AMD combo.  Now I understand the
situation better, thanks.

> >> 1. ubuntu audio setting use pactl to query audio card/output sink. Attachment is pactl output with audio runtime pm.
> >> 2. cat /proc/asound/card0/eld* can get nothing.
> >>
> >> Without audio runtime pm:
> >> 1. pactl can get available audio output/sink
> >> 2. can get eld info from eld#0.1
> >>
> >> IMO, the issue should be:
> >>
> >> Current operations like HDMI hotplug in/out, pactl command, they do
> >> not access audio HW, so the audio could not resume back at this
> >> period.
> > Sorry, not understood.  Why they don't access the audio hardware?
> This is my guess, since I do not get azx_runtime_resume() print info
> which I added. it maybe access HW during this period, but do not
> trigger audio resume progress.
> <https://elixir.bootlin.com/linux/v4.18-rc3/ident/azx_runtime_resume>
> >> Therefore, upper software could not get HDMI ELD info, can select a available card/output sink.
> >> I am also confuse that if there is no ELD info, how driver to steam audio device to wake up itself? It's sort of a chicken-or-egg question.
> > As long as it's i915 and HD-audio, the hotplug and ELD info transfer
> > doesn't trigger the runtime PM since it's done via the direct
> > callback.  And ELD value is cached in HD-audio side.
> Yeah, I have reviewed these code, it constructs ELD after reading
> EDID, and write them into HW buffer when set display mode.

If the controller chip supports "wake-enable" feature (HD-audio WAKEEN
register), it could be woken up at unsolicited event even during the
link power down.  But, your report implies that AMD controller doesn't
do this, or something missing there.  That's the likely cause of the
missing hotplug event.

So, if my understanding is right, the situation won't be different
even if you have a single AMD GPU.  And possibly a side-effect of the
latest fix to force link-down for AMD GPU.  Need to check it...


Takashi

> > The exception is that if the notification is done during the PM
> > operation.  But, the connection and ELD query is performed at the end
> > of codec resume, hence it'll be covered there.
> >
> > So in theory, ELD information should be passed from the GPU to
> > HD-audio no matter whether runtime PM is enabled or not.
> >
> >
> > BTW, please stop top-posting.  It makes the thread readability awfully
> > worse.
> >
> Sorry, I justed used outlook client.
> > thanks,
> >
> > Takashi
> >
> >> Thanks
> >> JimQu
> >>
> >> ________________________________________
> >> 发件人: Takashi Iwai <tiwai at suse.de>
> >> 发送时间: 2018年7月10日 1:09
> >> 收件人: Qu, Jim
> >> 抄送: Daniel Vetter; Alex Deucher; alsa-devel at alsa-project.org; amd-gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org; Deucher, Alexander
> >> 主题: Re: 答复: [alsa-devel]        答复: [PATCH] vgaswitchroo: set audio client id according to bound gpu client id
> >>
> >> On Mon, 09 Jul 2018 18:05:09 +0200,
> >> Qu, Jim wrote:
> >>> Hi Takashi,
> >>>
> >>> Not intel, but it is AMD APU+ AMD GFX, the APU has a local HDMI port for extension. And dGPU is only for offloading render via PRIME.
> >>>
> >>> Originally, the HDA driver before v4.17, there is a bug, that all the audio is set to CLIENT_DIS, so the when the dGPU suspend, the audio which is bound to iGPU will also be suspend.
> >>>
> >>> Now, after Lukas' patches. The audio will auto suspend. It make ubuntu audio setting could not detect HDMI audio, even if HDMI has light up.
> >> OK, and it has all necessary patches including the one Lukas
> >> suggested, right?
> >>
> >> If so, figure out what you're actually seeing as "PA could not detect
> >> HDMI audio".  For example, is it the HDMI (jack) detection (giving
> >> false even if it's connected)?  Or is it an error at opening the given
> >> device? Does the driver give the proper ELD bytes as well as the jack
> >> state?
> >>
> >>
> >> Takashi
> >>
> >>> Thanks
> >>> JimQu
> >>>
> >>> -----邮件原件-----
> >>> 发件人: Takashi Iwai <tiwai at suse.de>
> >>> 发送时间: 2018年7月9日 23:58
> >>> 收件人: Daniel Vetter <daniel at ffwll.ch>
> >>> 抄送: Alex Deucher <alexdeucher at gmail.com>; alsa-devel at alsa-project.org; amd-gfx at lists.freedesktop.org; Qu, Jim <Jim.Qu at amd.com>; dri-devel at lists.freedesktop.org; Deucher, Alexander <Alexander.Deucher at amd.com>
> >>> 主题: Re: [alsa-devel] 答复: [PATCH] vgaswitchroo: set audio client id according to bound gpu client id
> >>>
> >>> On Mon, 09 Jul 2018 17:56:43 +0200,
> >>> Daniel Vetter wrote:
> >>>> On Mon, Jul 09, 2018 at 05:04:22PM +0200, Takashi Iwai wrote:
> >>>>> On Mon, 09 Jul 2018 15:58:51 +0200,
> >>>>> Alex Deucher wrote:
> >>>>>> On Mon, Jul 9, 2018 at 6:16 AM, Qu, Jim <Jim.Qu at amd.com> wrote:
> >>>>>>> Hi Lukas,
> >>>>>>>
> >>>>>>> Thanks to your explanation, and see comments in line.
> >>>>>>>
> >>>>>>>
> >>>>>>> Do you need to runtime resume the HDA controller even if user
> >>>>>>> space isn't streaming audio?  Why, and in which situation exactly?
> >>>>>>>
> >>>>>>> Jim: OEM system uses pactl to queiry audio card and audio output sink, since the audio has power down by runtime pm, so the audio card and output sink are all unavailable. they could not select the available HDMI audio for audio playing.
> >>>>>>>
> >>>>>>> You're saying above that the HDA controller isn't runtime
> >>>>>>> resumed on hotplug of a display.  Is that necessary to retrieve ELD or something?
> >>>>>>> I'm not sure if there's code in the HDA driver to acquire a
> >>>>>>> runtime PM ref on HPD, but maybe it's necessary.  Or maybe the
> >>>>>>> code is there but somehow no HPD interrupt is received by the HDA driver?
> >>>>>>>
> >>>>>>> Jim: So far, I do not find any code about audio response HPD in kernel. the HPD interrupt will sent to user mode via uevent, not sure whether audio user mode driver can receive the event or not.
> >>>>>> On the gfx side at least, we can get a hotplug event via ACPI
> >>>>>> (depending on the OEM design) if displays are attached/detached
> >>>>>> while the dGPU is powered down.  I suppose the gfx driver could
> >>>>>> call into the audio driver during one of those events.  On the gfx
> >>>>>> side at least we just generate the gfx hotplug event and let userspace deal with it.
> >>>>> IMO, a more proper way would be to have the direct communication
> >>>>> between the graphics driver and the audio driver like i915 driver
> >>>>> does.  Then the audio driver can get plug/unplug event at more
> >>>>> accurate timing without races.
> >>>>>
> >>>>> (Though, it will cause another mess wrt the weak module dependency,
> >>>>> but it's another story :)
> >>>> Just don't do what snd-hda-intel did and instead implement the
> >>>> component stuff properly :-)
> >>> A patch is welcome :)
> >>>
> >>>
> >>> thanks,
> >>>
> >>> Takashi
> >>>
> >>>> -Daniel
> >>>>
> >>>>>
> >>>>> thanks,
> >>>>>
> >>>>> Takashi
> >>>>>
> >>>>>
> >>>>>> Alex
> >>>>>>
> >>>>>>> Thanks
> >>>>>>> JimQu
> >>>>>>>
> >>>>>>> ________________________________________
> >>>>>>> 发件人: Lukas Wunner <lukas at wunner.de>
> >>>>>>> 发送时间: 2018年7月9日 17:27
> >>>>>>> 收件人: Qu, Jim
> >>>>>>> 抄送: alsa-devel at alsa-project.org;
> >>>>>>> dri-devel at lists.freedesktop.org; Deucher, Alexander;
> >>>>>>> amd-gfx at lists.freedesktop.org
> >>>>>>> 主题: Re: [PATCH] vgaswitchroo: set audio client id according to
> >>>>>>> bound gpu client id
> >>>>>>>
> >>>>>>> On Mon, Jul 09, 2018 at 08:52:33AM +0000, Qu, Jim wrote:
> >>>>>>>> Now, I found the audio device will auto suspend even if the gpu
> >>>>>>>> is active, and if I plug in a HDMI device it also do not resume back.
> >>>>>>>>
> >>>>>>>> 1. Did you encounter similar issue before?
> >>>>>>>> 2. audio will auto suspend as default at beginning of boot, is
> >>>>>>>> it expect behaviour?
> >>>>>>> Yes, that's expected.  Once you start streaming audio to
> >>>>>>> attached displays, user space opens the codec device and this
> >>>>>>> causes the HDA controller to runtime resume.  If the discrete
> >>>>>>> GPU is suspended at that moment, it will be powered on and kept powered on as long as user space is streaming audio.
> >>>>>>>
> >>>>>>> Do you need to runtime resume the HDA controller even if user
> >>>>>>> space isn't streaming audio?  Why, and in which situation exactly?
> >>>>>>>
> >>>>>>> You're saying above that the HDA controller isn't runtime
> >>>>>>> resumed on hotplug of a display.  Is that necessary to retrieve ELD or something?
> >>>>>>> I'm not sure if there's code in the HDA driver to acquire a
> >>>>>>> runtime PM ref on HPD, but maybe it's necessary.  Or maybe the
> >>>>>>> code is there but somehow no HPD interrupt is received by the HDA driver?
> >>>>>>>
> >>>>>>> Thanks,
> >>>>>>>
> >>>>>>> Lukas
> >>>>>>> _______________________________________________
> >>>>>>> dri-devel mailing list
> >>>>>>> dri-devel at lists.freedesktop.org
> >>>>>>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
> >>>>>> _______________________________________________
> >>>>>> Alsa-devel mailing list
> >>>>>> Alsa-devel at alsa-project.org
> >>>>>> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
> >>>>> _______________________________________________
> >>>>> dri-devel mailing list
> >>>>> dri-devel at lists.freedesktop.org
> >>>>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
> >>>> --
> >>>> Daniel Vetter
> >>>> Software Engineer, Intel Corporation
> >>>> http://blog.ffwll.ch
> >>>>
> >> [2 pactl_with_runtimepm <application/octet-stream (base64)>]
> >>
> 
> [2  <text/html; utf-8 (8bit)>]
>

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