[alsa-devel] [RFC PATCH] ALSA: hda - Keep power link on for PantherPoint HDMI

[Takashi Iwai]

At Mon, 19 Nov 2012 15:14:45 +0100,
David Henningsson wrote:
> 
> On 11/07/2012 09:36 AM, Takashi Iwai wrote:
> > At Wed,  7 Nov 2012 09:22:33 +0100,
> > David Henningsson wrote:
> >>
> >> On some of the PantherPoint HDMI machines we currently enable, we're seeing
> >> trouble with unsol events, i e detecting monitor presence, especially when
> >> on battery and after suspend/resume.
> >>
> >> BugLink: https://bugs.launchpad.net/bugs/1075882
> >> Tested-by: Cyrus Lien <cyrus.lien at canonical.com>
> >> Signed-off-by: David Henningsson <david.henningsson at canonical.com>
> >> ---
> >>   sound/pci/hda/patch_hdmi.c |    8 ++++++--
> >>   1 file changed, 6 insertions(+), 2 deletions(-)
> >>
> >> So far this is the workaround we have found to be working. Sometimes, it also
> >> seems that "cat /proc/asound/cardx/codec#x" can also make the HDMI unsol event
> >> trigger, so that the problem fixes itself.
> >>
> >> We have not run any battery life tests to see if this causes more power consumption.
> >
> > Looks safe at least, so I applied to for-next branch to give more
> > testing.  If you find a better solution, let me know.
> 
> Jesse has now done a battery life test, both for idle machine and S3 
> machine, and both with HDMI connected and HDMI unconnected.
> 
> All differences in power consumption were within error margins. Given 
> that, should we consider sending this patch to stable?

Well, once when it hits to Linus tree.  It's in for-next branch, and I
don't want to rebase the branch.  So, wait for the next merge window,
which will happen likely in a couple of weeks.


thanks,

Takashi