From: Daniel Vetter <daniel@ffwll.ch>
To: Paulo Zanoni <przanoni@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH 5/9] drm/i915: CPT/PPT pch dp transcoder workaround
Date: Mon, 29 Oct 2012 16:38:16 +0100 [thread overview]
Message-ID: <20121029153816.GO5691@phenom.ffwll.local> (raw)
In-Reply-To: <CA+gsUGTWddRp6kFnD07QmZ6-SnP9Js4oDRgX5tgsMff3rc3tFA@mail.gmail.com>
On Fri, Oct 26, 2012 at 12:21:11PM -0200, Paulo Zanoni wrote:
> Hi
>
> 2012/10/26 Daniel Vetter <daniel.vetter@ffwll.ch>:
> > We need to set the timing override chicken bit after fdi link training
> > has completed and before we enable the dp transcoder. We also have to
> > clear that bit again after disabling the pch dp transcoder.
> >
> > See "Graphics BSpec: vol4g North Display Engine Registers [IVB],
> > Display Mode Set Sequence" and "Graphics BSpec: vol4h South Display
> > Engine Registers [CPT, PPT], South Display Engine Transcoder and FDI
> > Control, Transcoder Debug and DFT, TRANS_CHICKEN_2" bit 31:
> >
> > "Workaround : Enable the override prior to enabling the transcoder.
> > Disable the override after disabling the transcoder."
> >
> > While at it, use the _PIPE macro for the other TRANS_DP register.
>
> What confuses me is that the bit name is actually "Autotrain TimingGen
> Override" and after a quick check it seems we don't use autotrain.
> Also, by looking at the IVB mode set sequence it seems Auto Train is
> the *recommended* method since manual is listed as "testing only". So
> I'm not sure if we need this code now, but it seems we could try to
> implement the auto train...
Well, us using manual fdi train is a different matter altogether. And
since there's nothing in the docs indicating that we don't need this w/a
if we don't do autotraining, I prefer to just stick it into the code.
And Damien tried to do the auto training, but somehow it failed ...
> Also, I'd move the code that sets/unsets the chicken bit to
> intel_enable_transcoder/intel_disable_transcoder.
According to my reading of the modeset sequence we need to do this after
the fdi train is fully done, but before we enable the pch dp transcoder.
So I think this is the right place, and I can't actually move it anyplace
else. And since the pch dp transcoder is a cpt/ppt-only feature, it' fits
rather naturally.
Cheers, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
next prev parent reply other threads:[~2012-10-29 15:37 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-26 8:58 [PATCH 0/9] some ivb fdi b/c fixes Daniel Vetter
2012-10-26 8:58 ` [PATCH 1/9] drm/i915: shut up spurious message in intel_dp_get_hw_state Daniel Vetter
2012-10-26 14:01 ` Paulo Zanoni
2012-10-26 8:58 ` [PATCH 2/9] drm/i915: Write the FDI RX TU size reg at the right time Daniel Vetter
2012-10-27 11:51 ` Paulo Zanoni
2012-10-27 12:59 ` Daniel Vetter
2012-10-27 13:03 ` Paulo Zanoni
2012-10-27 13:04 ` Daniel Vetter
2012-10-27 13:18 ` Paulo Zanoni
2012-10-27 13:50 ` Daniel Vetter
2012-10-27 13:20 ` [PATCH] " Daniel Vetter
2012-10-26 8:58 ` [PATCH 3/9] drm/i915: set FDI_RX_MISC to recommended values on CPT/PPT Daniel Vetter
2012-10-27 12:02 ` Paulo Zanoni
2012-10-26 8:58 ` [PATCH 4/9] drm/i915: add comment about pch pll enabling rules Daniel Vetter
2012-10-27 12:15 ` Paulo Zanoni
2012-10-27 12:57 ` Daniel Vetter
2012-10-27 16:46 ` [PATCH] " Daniel Vetter
2012-10-29 12:02 ` Paulo Zanoni
2012-10-26 8:58 ` [PATCH 5/9] drm/i915: CPT/PPT pch dp transcoder workaround Daniel Vetter
2012-10-26 14:21 ` Paulo Zanoni
2012-10-29 15:38 ` Daniel Vetter [this message]
2012-10-29 17:02 ` Paulo Zanoni
2012-10-29 17:14 ` Daniel Vetter
2012-10-31 17:41 ` Paulo Zanoni
2012-10-26 8:58 ` [PATCH 6/9] drm/i915: BUG on impossible pch dp port Daniel Vetter
2012-10-26 15:04 ` Paulo Zanoni
2012-10-26 8:58 ` [PATCH 7/9] drm/i915: drop unnecessary check from fdi_link_train code Daniel Vetter
2012-10-26 15:32 ` Paulo Zanoni
2012-10-26 8:58 ` [PATCH 8/9] drm/i915: add ->display.modeset_global_resources callback Daniel Vetter
2012-10-27 12:18 ` Paulo Zanoni
2012-10-26 8:58 ` [PATCH 9/9] drm/i915: check fdi B/C lane sharing constraint Daniel Vetter
2012-10-27 12:56 ` Paulo Zanoni
2012-10-27 13:03 ` Daniel Vetter
2012-10-27 13:58 ` [PATCH] " Daniel Vetter
2012-10-29 12:06 ` Paulo Zanoni
2012-10-29 17:42 ` Daniel Vetter
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