diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2018-10-08 12:57:34 +0200 |
|---|---|---|
| committer | Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> | 2018-10-08 12:57:34 +0200 |
| commit | ceadddde8875bda7af3824244de3d93e386d08c1 (patch) | |
| tree | 0737a35880e5653b97407f073a6a10a9afed770c /drivers/video/fbdev/aty/atyfb.h | |
| parent | 68a958a915ca912b8ce71b9eea7445996f6e681e (diff) | |
| download | linux-ceadddde8875bda7af3824244de3d93e386d08c1.tar.bz2 | |
mach64: detect the dot clock divider correctly on sparc
On Sun Ultra 5, it happens that the dot clock is not set up properly for
some videomodes. For example, if we set the videomode "r1024x768x60" in
the firmware, Linux would incorrectly set a videomode with refresh rate
180Hz when booting (suprisingly, my LCD monitor can display it, although
display quality is very low).
The reason is this: Older mach64 cards set the divider in the register
VCLK_POST_DIV. The register has four 2-bit fields (the field that is
actually used is specified in the lowest two bits of the register
CLOCK_CNTL). The 2 bits select divider "1, 2, 4, 8". On newer mach64 cards,
there's another bit added - the top four bits of PLL_EXT_CNTL extend the
divider selection, so we have possible dividers "1, 2, 4, 8, 3, 5, 6, 12".
The Linux driver clears the top four bits of PLL_EXT_CNTL and never sets
them, so it can work regardless if the card supports them. However, the
sparc64 firmware may set these extended dividers during boot - and the
mach64 driver detects incorrect dot clock in this case.
This patch makes the driver read the additional divider bit from
PLL_EXT_CNTL and calculate the initial refresh rate properly.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Ville Syrjälä <syrjala@sci.fi>
Cc: stable@vger.kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Diffstat (limited to 'drivers/video/fbdev/aty/atyfb.h')
| -rw-r--r-- | drivers/video/fbdev/aty/atyfb.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/video/fbdev/aty/atyfb.h b/drivers/video/fbdev/aty/atyfb.h index 8235b285dbb2..d09bab3bf224 100644 --- a/drivers/video/fbdev/aty/atyfb.h +++ b/drivers/video/fbdev/aty/atyfb.h @@ -333,6 +333,8 @@ extern const struct aty_pll_ops aty_pll_ct; /* Integrated */ extern void aty_set_pll_ct(const struct fb_info *info, const union aty_pll *pll); extern u8 aty_ld_pll_ct(int offset, const struct atyfb_par *par); +extern const u8 aty_postdividers[8]; + /* * Hardware cursor support @@ -359,7 +361,6 @@ static inline void wait_for_idle(struct atyfb_par *par) extern void aty_reset_engine(const struct atyfb_par *par); extern void aty_init_engine(struct atyfb_par *par, struct fb_info *info); -extern u8 aty_ld_pll_ct(int offset, const struct atyfb_par *par); void atyfb_copyarea(struct fb_info *info, const struct fb_copyarea *area); void atyfb_fillrect(struct fb_info *info, const struct fb_fillrect *rect); |