From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Richter <thor@math.tu-berlin.de>
Subject: Workaround for flicker with panning on the i830 - found
 a way for tiled displays
Date: Fri, 15 Nov 2013 14:16:11 +0100
Message-ID: <52861E9B.5080509@math.tu-berlin.de>
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To: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx <intel-gfx@lists.freedesktop.org>
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Hi Daniel, hi others,

did even more experiments. I guess I understand now better. Indeed, the 
trouble seems to be the watermark levels. I played more
with all that, and the real culprit seems to be the FW_BLC register 
controlling the watermarks.

On the i830 with the current settings, it is defined to be 0x1080304 
which sets the watermark a bit too low. If I set it to
0x1080306 instead, I get a stable display in all panning positions 
(hurray!).

I would like to fix this, but I guess I would need to understand the 
logic a little bit better. At the time being, you probably better
put the linear frame buffer workaround on hold, it looks I really got 
something here.

Greetings,
     Thomas