From: Jesse Barnes <jbarnes@virtuousgeek.org>
To: "Lin, Mengdong" <mengdong.lin@intel.com>
Cc: "intel-gfx@lists.freedesktop.org"
<intel-gfx@lists.freedesktop.org>,
"Widawsky, Benjamin" <benjamin.widawsky@intel.com>
Subject: Re: How will Gfx driver support runtime PM on Haswell?
Date: Thu, 22 Aug 2013 16:07:08 -0700 [thread overview]
Message-ID: <20130822160708.47b5f5d0@jbarnes-desktop> (raw)
In-Reply-To: <F46914AEC2663F4A9BB62374E5EEF8F80131D38F@SHSMSX101.ccr.corp.intel.com>
On Wed, 21 Aug 2013 15:29:17 +0000
"Lin, Mengdong" <mengdong.lin@intel.com> 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
next prev parent reply other threads:[~2013-08-22 23:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-21 15:29 How will Gfx driver support runtime PM on Haswell? Lin, Mengdong
2013-08-22 23:07 ` Jesse Barnes [this message]
2013-08-23 16:49 ` Paulo Zanoni
2013-08-23 17:10 ` Jesse Barnes
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