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authorRisto Suominen <Risto.Suominen@gmail.com>2009-01-13 20:09:30 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-02-02 17:08:25 +1100
commit7fbb7cadd062baf299fd8b26a80ea99da0c3fe01 (patch)
tree5992150dd976a50d81fe5ba472397ab26507494c /drivers
parent59b608c2c33feacc8be281ec3ba9ca2a3a5cb9a7 (diff)
fbdev/atyfb: Fix DSP config on some PowerMacs & PowerBooks
Since the complete re-write in 2.6.10, some PowerMacs (At least PowerMac 5500 and PowerMac G3 Beige rev A) with ATI Mach64 chip have suffered from unstable columns in their framebuffer image. This seems to depend on a value (4) read from PLL_EXT_CNTL register, which leads to incorrect DSP config parameters to be written to the chip. This patch uses a value calculated by aty_init_pll_ct instead, as a starting point. There are questions as to whether this should be extended to other platforms or maybe made dependent on specific chip types, but in the meantime, this has been tested on various powermacs and works for them so let's commit it. Signed-off-by: Risto Suominen <Risto.Suominen@gmail.com> Tested-by: Michael Pettersson <mike@it.uu.se> Cc: <stable@kernel.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/video/aty/mach64_ct.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/video/aty/mach64_ct.c b/drivers/video/aty/mach64_ct.c
index c50c7cf26fe..2745b853948 100644
--- a/drivers/video/aty/mach64_ct.c
+++ b/drivers/video/aty/mach64_ct.c
@@ -8,6 +8,9 @@
#include <asm/io.h>
#include <video/mach64.h>
#include "atyfb.h"
+#ifdef CONFIG_PPC
+#include <asm/machdep.h>
+#endif
#undef DEBUG
@@ -536,6 +539,14 @@ static int __devinit aty_init_pll_ct(const struct fb_info *info,
pll->ct.xclk_post_div_real = postdividers[xpost_div];
pll->ct.mclk_fb_div = q * pll->ct.xclk_post_div_real / 8;
+#ifdef CONFIG_PPC
+ if (machine_is(powermac)) {
+ /* Override PLL_EXT_CNTL & 0x07. */
+ pll->ct.xclk_post_div = xpost_div;
+ pll->ct.xclk_ref_div = 1;
+ }
+#endif
+
#ifdef DEBUG
pllmclk = (1000000 * pll->ct.mclk_fb_mult * pll->ct.mclk_fb_div) /
(par->ref_clk_per * pll->ct.pll_ref_div);