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path: root/drivers/video/fbdev/tridentfb.c
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Diffstat (limited to 'drivers/video/fbdev/tridentfb.c')
-rw-r--r--drivers/video/fbdev/tridentfb.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/video/fbdev/tridentfb.c b/drivers/video/fbdev/tridentfb.c
index 742971304717..01b43e9ce941 100644
--- a/drivers/video/fbdev/tridentfb.c
+++ b/drivers/video/fbdev/tridentfb.c
@@ -673,8 +673,14 @@ static int get_nativex(struct tridentfb_par *par)
static inline void set_lwidth(struct tridentfb_par *par, int width)
{
write3X4(par, VGA_CRTC_OFFSET, width & 0xFF);
- write3X4(par, AddColReg,
- (read3X4(par, AddColReg) & 0xCF) | ((width & 0x300) >> 4));
+ /* chips older than TGUI9660 have only 1 width bit in AddColReg */
+ /* touching the other one breaks I2C/DDC */
+ if (par->chip_id == TGUI9440 || par->chip_id == CYBER9320)
+ write3X4(par, AddColReg,
+ (read3X4(par, AddColReg) & 0xEF) | ((width & 0x100) >> 4));
+ else
+ write3X4(par, AddColReg,
+ (read3X4(par, AddColReg) & 0xCF) | ((width & 0x300) >> 4));
}
/* For resolutions smaller than FP resolution stretch */