Re: [BUG][REGRESSION] mangled display since -rc1

[Martin Kepplinger]

Am 2016-11-07 um 09:24 schrieb Jani Nikula:
> On Sun, 06 Nov 2016, Martin Kepplinger <martink@xxxxxxxxx> wrote:
>> I did not file a bug in bugzilla yet. I haven't given up that we can fix
>> this here before the release. I've ignored it the last few days though.
> 
> You say it like filing the bug report and having the bug fixed are
> mutually exclusive things...
> 
> Pretty please? It's easier for us to direct folks at the bug, with
> history and logs in one place. I realize only Daniel and me were Cc'd
> here, not intel-gfx list.
> 
> Also, please double check your bisect. Not sure why the finger points at
> i915 when the bisect points at iommu merge.
> 
> 
> BR,
> Jani.
> 
> 

Chris Clayton wrote off list and the mentioned patch fixes the problem
for me too, as it does for others. I hope it make it's way into the tree
soon:


-------- Weitergeleitete Nachricht --------
Betreff: Fwd: Re: Redraw issues on i915 on 4.9-rc
Datum: Mon, 7 Nov 2016 13:48:14 +0000
Von: Chris Clayton <chris2553@xxxxxxxxxxxxxx>
An: martink@xxxxxxxxx

Hi Martin.


I can't contact you through LKML because I'm not subscribed, but I've
been working with Chris Wilson, one of the Intel
DRM developers to analyse and fix the corruption. We've got a patch that
fixes it for me and Norbert who also reported
the problem. The patch is at the bottom of this message.

Hope it helps.

Chris


-------- Forwarded Message --------
Subject: Re: Redraw issues on i915 on 4.9-rc
Date: Mon, 7 Nov 2016 09:25:59 +0000
From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
To: Chris Clayton <chris2553@xxxxxxxxxxxxxx>
CC: Norbert Preining <preining@xxxxxxxx>

On Mon, Nov 07, 2016 at 09:16:38AM +0000, Chris Clayton wrote:
> Hello again.
>
> I wasn't at all happy about the last bisect I did, so I've run it
again and this time spent at least 30 minutes using my
> system before marking a kernel as good. I've also noticed that when I
boot a bad kernel, the graphics associated with
> three of my desktop icons do not get drawn, so that helps.
>
> The outcome of the bisection is:
>
> a61007a83a4671da77210790997d5c8c92ed87ea is the first bad commit
> commit a61007a83a4671da77210790997d5c8c92ed87ea
> Author: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Date:   Thu Aug 18 17:17:02 2016 +0100
>
>     drm/i915: Fix partial GGTT faulting

That's just the enabling patch, everything was meant to be in place by
then.

Oh noes, care to try:


diff --git a/drivers/gpu/drm/i915/i915_gem.c
b/drivers/gpu/drm/i915/i915_gem.c
index c642385bb236..a52b40bbac6f 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1837,7 +1837,7 @@ int i915_gem_fault(struct vm_area_struct *area,
struct vm_fault *vmf)
                /* Use a partial view if it is bigger than available
space */
                chunk_size = MIN_CHUNK_PAGES;
                if (i915_gem_object_is_tiled(obj))
-                       chunk_size = max(chunk_size, tile_row_pages(obj));
+                       chunk_size = roundup(chunk_size,
tile_row_pages(obj));
                 memset(&view, 0, sizeof(view));
                view.type = I915_GGTT_VIEW_PARTIAL;

-- 
Chris Wilson, Intel Open Source Technology Centre