At Thu, 18 Jul 2013 01:00:07 +0000, Wang, Xingchao wrote: > > Hi Paulo/Daniel, > > Do you agree to export an API in gfx side for eDP case? > Basically the api will let audio drver know which pipe in use. i.e. in the eDP only caes, audio driver > Will know gfx is not using HDMI/DP and would like to let power-well off. > As there's the conflict when user expect display audio driver always active but gfx need audio driver off. > Audio driver could make decision to release power-well if it knows the eDP only case through the API. I don't understand this requirement. We know that no HDMI/DP is plugged in. The problem Paulo has seen is that the power-saving isn't kicked off just because it's turned off explicitly. In other words, this is a system setup issue, after all. OTOH, if HDMI/DP can be never plugged in, creating a sound device itself doesn't make sense at all. If this is the case, we may improve the audio driver code just to skip the devices with such configurations. > OTOH, I think audio driver could also export an API for gfx side, if gfx driver need audio driver release power-well but it's in usage, > It will call this API and audio drvier will release power-well accordingly. > > This change make HDMI/DP hotplug handling complicated in audio driver side, if audio driver release power-well, it would enter suspend mode. > Meanwhile the user may expect it's in active mode, this may cause some confuse. Yes. In general, such a force-to-suspend-the-active-stream event should happen only when the device is really unavailable, but never be done just for saving power. Takashi > Thanks > --xingchao > > > -----Original Message----- > > From: Wang, Xingchao > > Sent: Thursday, July 18, 2013 7:18 AM > > To: 'Takashi Iwai'; David Henningsson; Paulo Zanoni > > Cc: alsa-devel@xxxxxxxxxxxxxxxx; Daniel Vetter; daniel.vetter@xxxxxxxx; > > intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Wang xingchao; Girdwood, Liam R; Jin, Gordon > > Subject: RE: [alsa-devel] [PATCH 0/4 V7] Power-well API > > implementation for Haswell > > > > > > > > > -----Original Message----- > > > From: Takashi Iwai [mailto:tiwai@xxxxxxx] > > > Sent: Wednesday, July 17, 2013 10:22 PM > > > To: David Henningsson > > > Cc: Paulo Zanoni; Wang, Xingchao; alsa-devel@xxxxxxxxxxxxxxxx; Daniel > > > Vetter; daniel.vetter@xxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Wang > > > xingchao; Girdwood, Liam R; Jin, Gordon > > > Subject: Re: [alsa-devel] [PATCH 0/4 V7] Power-well API > > > implementation for Haswell > > > > > > At Wed, 17 Jul 2013 16:05:43 +0200, > > > David Henningsson wrote: > > > > > > > > On 07/17/2013 04:00 PM, Takashi Iwai wrote: > > > > > At Wed, 17 Jul 2013 10:31:26 -0300, Paulo Zanoni wrote: > > > > >> > > > > >> 2013/7/17 Wang, Xingchao <xingchao.wang@xxxxxxxxx>: > > > > >>> > > > > >>> > > > > >>>> -----Original Message----- > > > > >>>> From: Takashi Iwai [mailto:tiwai@xxxxxxx] > > > > >>>> Sent: Wednesday, July 17, 2013 4:18 PM > > > > >>>> To: Wang, Xingchao > > > > >>>> Cc: Paulo Zanoni; alsa-devel@xxxxxxxxxxxxxxxx; Daniel Vetter; > > > > >>>> daniel.vetter@xxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Wang > > > > >>>> xingchao; Girdwood, Liam R; david.henningsson@xxxxxxxxxxxxx > > > > >>>> Subject: Re: [alsa-devel] [PATCH 0/4 V7] Power-well > > > > >>>> API implementation for Haswell > > > > >>>> > > > > >>>> At Wed, 17 Jul 2013 08:03:38 +0000, Wang, Xingchao wrote: > > > > >>>>> > > > > >>>>> > > > > >>>>> > > > > >>>>>> -----Original Message----- > > > > >>>>>> From: Takashi Iwai [mailto:tiwai@xxxxxxx] > > > > >>>>>> Sent: Wednesday, July 17, 2013 3:34 PM > > > > >>>>>> To: Wang, Xingchao > > > > >>>>>> Cc: Paulo Zanoni; alsa-devel@xxxxxxxxxxxxxxxx; Daniel Vetter; > > > > >>>>>> daniel.vetter@xxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Wang > > > > >>>>>> xingchao; Girdwood, Liam R; david.henningsson@xxxxxxxxxxxxx > > > > >>>>>> Subject: Re: [alsa-devel] [PATCH 0/4 V7] > > > > >>>>>> Power-well API implementation for Haswell > > > > >>>>>> > > > > >>>>>> At Wed, 17 Jul 2013 02:52:41 +0000, Wang, Xingchao wrote: > > > > >>>>>>> > > > > >>>>>>> Hi Takashi/Paulo, > > > > >>>>>>> > > > > >>>>>>>>>> would you change it to "auto" and test again. > > > > >>>>>>>>>> Runtime power save should be enabled with "auto". > > > > >>>>>>>>> > > > > >>>>>>>>> Doesn't solve the problem. Should I open a bug report > > > somewhere? > > > > >>>>>>>>> Having the power well enabled prevents some power saving > > > > >>>>>>>>> features from the graphics driver. > > > > >>>>>>>> > > > > >>>>>>>> Is the HD-audio power-saving itself working? You can check > > > > >>>>>>>> it via watching /sys/class/hwC*/power_{on|off}_acct files. > > > > >>>>>>>> > > > > >>>>>>>> power_save option has to be adjusted appropriately. Note > > > > >>>>>>>> that many DEs change this value dynamically per AC-cable > > > > >>>>>>>> plug/unplug depending on the configuration, and often it's > > > > >>>>>>>> set to 0 (= no power save) when AC-cable is plugged. > > > > >>>>>>>> > > > > >>>>>>> [Wang, Xingchao] Paulo used a new Ultrabook board with > > > > >>>>>>> charger connected, > > > > >>>>>> and see the default parameter "auto=on". > > > > >>>>>>> In such scenario, power-well is always occupied by Display > > > > >>>>>>> audio controller. Moreover, in this board, if no external > > > > >>>>>>> monitors connected, It's > > > > >>>>>> using internal eDP and totally no audio support. Power-well > > > > >>>>>> usage in such case also blocks some eDP features as Paulo told me. > > > > >>>>>>> > > > > >>>>>>> So I think it's not a good idea to break the rule of power > > > > >>>>>>> policy when charger > > > > >>>>>> connected but it's necessary to add support in this particular case. > > > > >>>>>>> Takashi, do you think it's acceptable to let Display audio > > > > >>>>>>> controller/codec > > > > >>>>>> suspend in such case? > > > > >>>>>> > > > > >>>>>> Do you mean the driver enables the powersave forcibly? > > > > >>>>> > > > > >>>>> Yes. I mean call pm_runtime_allow() for the power-well HD-A > > > controller. > > > > >>>>> > > > > >>>>>> Then, no, not in general. > > > > >>>>>> > > > > >>>>>> If the default parameter of autopm is the problem, this > > > > >>>>>> should be changed, instead of forcing the policy in the driver. > > > > >>>>>> > > > > >>>>>> OTOH, the audio codec's powersave policy is governed by the > > > > >>>>>> power_save option and it's set up dynamically by the desktop > > system. > > > > >>>>>> We shouldn't override it in the driver. > > > > >>>>>> > > > > >>>>>> If the power well *must* be off when only an eDP is used (e.g. > > > > >>>>>> otherwise the hardware doesn't work properly), then it's a > > > > >>>>>> different story. Is it the case? And what exactly would be the > > > > >>>>>> problem? > > > > >>>>> In the eDP only case, no audio is needed for the HD-A > > > > >>>>> controller, so it's > > > > >>>> wasting power in current design. > > > > >>>>> I think Paulo or Daniel could explain more details on the impact. > > > > >>>> > > > > >>>> Consuming more power is the expected behavior. What else? > > > > >>>> > > > > >>>> > > > > >>>>>> If it's the case, controlling the power well based on the > > > > >>>>>> runtime PM is likely a bad design, as it relies on the > > > > >>>>>> parameter user > > > sets. > > > > >>>>>> (And remember that the power-saving of the audio can be > > > > >>>>>> disabled completely via Kconfig, too.) > > > > >>>>> From audio controller's point of view, if it's asked be > > > > >>>>> active, it needs power > > > > >>>> and should request power-well from gfx side. > > > > >>>>> In above case, audio controller should not be active but user > > > > >>>>> set it be > > > > >>>> "active". > > > > >>>> > > > > >>>> By setting the autopm "on", user expects that no runtime PM > > happens. > > > > >>>> In other words, the audio controller must be kept active as > > > > >>>> long as this parameter is set. And this is the parameter user > > > > >>>> controls, and not what the driver forcibly sets. > > > > >>> > > > > >>> Okay, become clear now. :) > > > > >>> So I think the conflict for Paulo becomes, in eDP caes, if audio > > > > >>> is active > > > and requested power-well, some eDP feature was under impact? > > > > >>> Paulo, would you clarify this in more details? > > > > >> > > > > >> On our driver we try to disable the power well whenever possible, > > > > >> as soon as possible. We don't change our behavior based on power > > > > >> AC or other user-space modifiable behavior (except the > > > > >> i915.disable_power_well Kernel option). If the power well is not > > > > >> disabled we can't enable some features, like PSR (panel self > > > > >> refresh, and eDP feature) or PC8, which is another power-saving > > > > >> feature. This will also make our QA procedures a lot more complex > > > > >> since when we want to test specific features (e.g., PSR, PC8) > > > > >> we'll have to disconnect the AC adapter or run scripts. So the > > > > >> behavior/predictability of our driver will be based on the Audio > > > > >> driver > > > power management policies. > > > > > > > > > > So all missing feature are about the power saving? > > > > > > > > > >> I am not so experienced with general Linux Power Management code, > > > > >> so maybe the way the Audio driver is behaving is just the usual > > > > >> way, but I have to admit I was expecting the audio driver would > > > > >> only require the power well when it is actually needed, and > > > > >> release it as soon as possible. > > > > > > > > > > It would behave so, if all setups are for power-saving. > > > > > > > > > > But, in your case, the runtime PM control attribute shows "on"; it > > > > > implies that the runtime PM is effectively disabled, thus > > > > > disabling power well is also impossible (because it would require > > > > > turning off the audio controller, too). > > > > > > > > So, if the machine only has an eDP (which has no audio function in > > > > itself, right?) and never HDMI, DP output because there are no such > > > > physical ports, the audio controller has no function. > > > > Maybe we can, before doing anything else, ask the video driver first > > > > if this is the case, and if so, never create the sound card at all, > > > > and just leave things the way the video driver wants? > > > > > > Well, doesn't BIOS mark HDMI/DP audio pins as unused? Then the audio > > > driver won't create any instances. Of course, we can optimize such a > > > case, indeed. > > > > As I know, the eDP only case doesnot mean no HDMI/DP support. User would > > plug in HDMI/DP monitor at any time. > > So diable audio controller totoally is not a good idea. :(. > > Paulo, is that correct for you case? > > > > --xingchao > > > > > > > > > Takashi > _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
