| Message ID | alpine.LRH.2.02.1405150652270.19101@file01.intranet.prod.int.rdu2.redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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
Index: linux-3.14/drivers/video/matrox/matroxfb_base.h =================================================================== --- linux-3.14.orig/drivers/video/matrox/matroxfb_base.h 2014-04-08 00:35:19.460051657 +0200 +++ linux-3.14/drivers/video/matrox/matroxfb_base.h 2014-05-03 18:38:18.882396833 +0200 @@ -698,7 +698,7 @@ void matroxfb_unregister_driver(struct m #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
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 --- drivers/video/matrox/matroxfb_base.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html