From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Date: Fri, 23 May 2014 10:45:04 +0000 Subject: Re: [PATCH] matroxfb: perform a dummy read of M_STATUS Message-Id: <537F26B0.4070608@ti.com> MIME-Version: 1 Content-Type: multipart/mixed; boundary="nUSsJWXB7VPQrKhmNK6aiKRpipHgntrUo" List-Id: References: In-Reply-To: To: linux-fbdev@vger.kernel.org --nUSsJWXB7VPQrKhmNK6aiKRpipHgntrUo Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 15/05/14 13:58, Mikulas Patocka wrote: > I had occasional screen corruption with the matrox framebuffer driver a= nd > I found out that the reason for the corruption is that the hardware > blitter accesses the videoram while it is being written to. >=20 > 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. >=20 > Since applying this patch, I had no screen corruption at all. >=20 > Signed-off-by: Mikulas Patocka > Cc: stable@vger.kernel.org >=20 Queued for 3.16. Tomi --nUSsJWXB7VPQrKhmNK6aiKRpipHgntrUo Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJTfya3AAoJEPo9qoy8lh71aMQP/jsSxByzcDT+uWYUal2YH4l0 gGRKNiai0LB+Euq7483IZ+e/KsCekWw3QPSYsXFQcy89kLyOSyJU1N5+hsdRLBi3 ER205uKYu6Ifb1ekBR0YY/XITVyI0PXqYiVS49+wUbJ1hVAPSDpIrHRgOuoLm3/A fzmmmJRkoH5aMs5G5k2/vHHynjtHw6X/IVmVoyFT+LsIk7ao6myKa4kfHIl8p7qy YwpKwvw75ckfo9eQFeq95VHjYZaa03v4Ug+3MqucFC9+wm7z80MTdfEQV6t75IxS B9S0h2p55Lj2UjtHmTmPb5+GDn2LnNvrZjcLXy9WS+LOe/BAUlnFFP2YVolhlO25 GNkHFDUsEjcUZ5vKYiWoM3+peXMhBGU83BWsawutGK3zOmIRjDPeMeeO8dFYTcmo iHS/XR2jD2eVzP93jkk0KjTpMxTiSmB+WsaMcS2IfPQlsLIbu0+p5ra2lLt4VGrl nSJlNU+HYq9p2+teMK5TzcgOBf+cLAQbVZJluU0yShzv0dcBhtlcHzC3OOtouQ2I 1DDsV2HgvmFsb0ecbBvoWkz8criXDrRQEODtZ6SLSciOzkZm6D3A2l1pGCJ4lIZs 3aYTafy8tiuEajKNdWSBQeVjDyMTMMPbrr7EYh8TJypbZw7LtkALaJ3d8LyzXqkY /+CF4wmysdxHHdMACBHs =ceKr -----END PGP SIGNATURE----- --nUSsJWXB7VPQrKhmNK6aiKRpipHgntrUo--