On Wed, 21 Aug 2013 15:29:17 +0000 "Lin, Mengdong" <mengdong.lin@xxxxxxxxx> wrote: > Hi Ben, > > How will Gfx driver support runtime PM on Haswell? Will the Gfx driver trigger "Adapter Power State" notification to BIOS when GPU switch state between D0 and D3? > > We need to support RTD3 for HD-A legacy audio on Haswell Ultrabook. And this depends on Gfx driver to implement two BIOS notifications. > > Here is the background of this dependency: > The target of HD-Audio RTD3 is that BIOS can power off the on-board 3rd party audio codec to save power in S0. This would help to save ~60mW. > Please note that audio driver cannot power off the codec, because the codec power is controlled by some GPIO which is board specific. > > The BIOS will power off the audio codec when three requirements are met: > > (1) System is running on battery > > (2) HD-Audio controller is in D3. Means no active audio application is using the audio devices. > > (3) All displays are off. This means system is in "User-Absent Mode", and a long latency for devices to resume back to D0 is allowed, such as ~300ms to power on the audio codec. > > For the 3rd requirement, BIOS needs Gfx driver to tell whether the system is in user-absent mode. It needs Gfx driver to triger two SCI SW notifications: Display Power State Notification and Adapter Power State Notification. > 'Display Power State Notification' was implemented by Jani. But we were told that 'Adapter Power State' notification needs Gfx driver to support runtime PM at first. > > So would you please share some information about runtime PM support in Gfx driver? Paulo was going to test this on top of his PC8+ patchset. AFAFIK the only thing we need to do is put the device into D3 when we enter the PC8+ mode, and the BIOS will do the right thing (when we use the OpRegion stuff Jani did anyway). Paulo, are you still out celebrating the PC8 bits or have you had a chance to try this yet? -- Jesse Barnes, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
