[Intel-gfx] [PATCH] detect hdmi monitor by reading edid

[Eric Anholt]

On Tue, 2009-06-30 at 13:44 +0800, Ma, Ling wrote:
> 
> >-----Original Message-----
> >From: intel-gfx-bounces at lists.freedesktop.org
> >[mailto:intel-gfx-bounces at lists.freedesktop.org] On Behalf Of Keith Packard
> >Sent: 2009年6月29日 23:07
> >To: Ma, Ling
> >Cc: intel-gfx at lists.freedesktop.org
> >Subject: Re: [Intel-gfx] [PATCH] detect hdmi monitor by reading edid
> >
> >On Mon, 2009-06-29 at 14:41 +0800, ling.ma at intel.com wrote:
> >> We detect HDMI output status by setting interrupt enable bit,
> >> then read interrupt status, which is effective for most cases.
> >> However G4x platform will indicate incorrect detection result
> >> even if current output is HDMI monitor. The patch intends
> >> to read edid, then determin connect status by EDID type.
> >
> >Can you describe the precise errors in detection you're seeing here?
> >From my experience, as the hotplug bits are shared among multiple
> >outputs, they will never provide a false-positive reading.
> >
> We run into two related bugs #21322 and #21084
> For #21322, The G43 can not find dvi monitor by hot plug approach.
> For #21084   There are 2 root causes, one is in KMS Q45( DQ45EK in our
> lab)  connected by VGA through DVI-I can't fetch EDID info, another is
> the it will mistake VGA as HDMI monitor.
> Our original approach is to set Hot Plug Interrupt Detect Enable, then
> read corresponding live state bit. However According to the HW team,
> live status detection need special board design, and won't work on all
> boards.
> Meanwhile I ever have seen bios code for G4X always read first 4 bytes
> of EDID to detect HDMI monitor and not use hot plug approach. 

So, if we're not doing hotplug interrupt based detection any more,
doesn't that mean that the PEG_BAND_GAP_DATA workaround doesn't need to
stay any more?

-- 
Eric Anholt
eric at anholt.net                         eric.anholt at intel.com


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