From: Tomi Valkeinen <tomi.valkeinen@ti.com>
To: linux-fbdev@vger.kernel.org
Subject: Re: [PATCH] matroxfb: perform a dummy read of M_STATUS
Date: Fri, 23 May 2014 10:45:04 +0000 [thread overview]
Message-ID: <537F26B0.4070608@ti.com> (raw)
In-Reply-To: <alpine.LRH.2.02.1405150652270.19101@file01.intranet.prod.int.rdu2.redhat.com>
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On 15/05/14 13:58, Mikulas Patocka wrote:
> I had occasional screen corruption with the matrox framebuffer driver and
> I found out that the reason for the corruption is that the hardware
> blitter accesses the videoram while it is being written to.
>
> The matrox driver has a macro WaitTillIdle() that should wait until the
> blitter is idle, but it sometimes doesn't work. I added a dummy read
> mga_inl(M_STATUS) to WaitTillIdle() to fix the problem. The dummy read
> will flush the write buffer in the PCI chipset, and the next read of
> M_STATUS will return the hardware status.
>
> Since applying this patch, I had no screen corruption at all.
>
> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
> Cc: stable@vger.kernel.org
>
Queued for 3.16.
Tomi
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prev parent reply other threads:[~2014-05-23 10:45 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-15 10:58 [PATCH] matroxfb: perform a dummy read of M_STATUS Mikulas Patocka
2014-05-23 10:45 ` Tomi Valkeinen [this message]
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