From: Tomi Valkeinen <tomi.valkeinen@ti.com>
To: Mikulas Patocka <mpatocka@redhat.com>,
Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] framebuffer: fix screen corruption when copying
Date: Tue, 30 Sep 2014 10:41:34 +0000 [thread overview]
Message-ID: <542A88DE.6080301@ti.com> (raw)
In-Reply-To: <alpine.LRH.2.02.1409161236550.3150@file01.intranet.prod.int.rdu2.redhat.com>
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On 16/09/14 19:38, Mikulas Patocka wrote:
> The function bitcpy_rev has a bug that may result in screen corruption.
> The bug happens under these conditions:
> * the end of the destination area of a copy operation is aligned on a long
> word boundary
> * the end of the source area is not aligned on a long word boundary
> * we are copying more than one long word
>
> In this case, the variable shift is non-zero and the variable first is
> zero. The statements FB_WRITEL(comp(d0, FB_READL(dst), first), dst) reads
> the last long word of the destination and writes it back unchanged
> (because first is zero). Correctly, we should write the variable d0 to the
> last word of the destination in this case.
>
> This patch fixes the bug by introducing and extra test if first is zero.
>
> The patch also removes the references to fb_memmove in the code that is
> commented out because fb_memmove was removed from framebuffer subsystem.
Thanks, queued for 3.18.
Tomi
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prev parent reply other threads:[~2014-09-30 10:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-16 16:38 [PATCH] framebuffer: fix screen corruption when copying Mikulas Patocka
2014-09-17 6:44 ` Geert Uytterhoeven
2014-09-17 11:44 ` Mikulas Patocka
2014-09-30 10:41 ` Tomi Valkeinen [this message]
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