diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2014-05-15 14:58:24 +0400 |
|---|---|---|
| committer | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2014-05-23 14:44:25 +0400 |
| commit | 972754cfaee94d6e25acf94a497bc0a864d91b7e (patch) | |
| tree | b6d0e5a15c896c2c47c6f3be6813cf8045b8aca3 /drivers/video/fbdev/matrox | |
| parent | 80c68c1e2e801a14d718f2ab9690398a864aa37c (diff) | |
| download | linux-972754cfaee94d6e25acf94a497bc0a864d91b7e.tar.xz | |
matroxfb: perform a dummy read of M_STATUS
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
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Diffstat (limited to 'drivers/video/fbdev/matrox')
| -rw-r--r-- | drivers/video/fbdev/matrox/matroxfb_base.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/video/fbdev/matrox/matroxfb_base.h b/drivers/video/fbdev/matrox/matroxfb_base.h index 556d96ce40bf..89a8a89a5eb2 100644 --- a/drivers/video/fbdev/matrox/matroxfb_base.h +++ b/drivers/video/fbdev/matrox/matroxfb_base.h @@ -698,7 +698,7 @@ void matroxfb_unregister_driver(struct matroxfb_driver* drv); #define mga_fifo(n) do {} while ((mga_inl(M_FIFOSTATUS) & 0xFF) < (n)) -#define WaitTillIdle() do {} while (mga_inl(M_STATUS) & 0x10000) +#define WaitTillIdle() do { mga_inl(M_STATUS); do {} while (mga_inl(M_STATUS) & 0x10000); } while (0) /* code speedup */ #ifdef CONFIG_FB_MATROX_MILLENIUM |