Seth/kernel_amazon_mt8127-common
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

matroxfb: perform a dummy read of M_STATUS

Browse Source 
commit 972754cfaee94d6e25acf94a497bc0a864d91b7e upstream.

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>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mikulas Patocka
2014-05-15 06:58:24 -04:00
committed by Greg Kroah-Hartman
parent dc10f332a7
commit 031767d310
1 changed files with 1 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/video/matrox/matroxfb_base.h
+1 -1
View File
@@ -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