> -----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. > > 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". Thanks --xingchao > > > Takashi _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
