projects/linux·commit 8690ba44

[PATCH] video/aty/mach64_ct.c: fix bogus delay loop

8690ba44 · David Miller <[email protected]> · 2007-03-05 01:35:36 -08:00

CT based mach64 cards were reported to hang on sparc64 boxes when
compiled with gcc-4.1.x and later.

Looking at this piece of code, it's no surprise.  A critical
delay was implemented as an empty for() loop, and gcc 4.0.x
and previous did not optimize it away, so we did get a delay.

But gcc-4.1.x and later can optimize it away, and we get crashes.

Use a real udelay() to fix this.  Fix verified on SunBlade100.

Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Commit
8690ba446defe2e2b81803756c099d2943dfd5fd
Parents
8f485612

Changes

1 files changed · +1 −2

FileStatusAddDelContent
drivers/video/aty/mach64_ct.cmodified+1−2View file

drivers/video/aty/mach64_ct.c

View file
diff --git a/drivers/video/aty/mach64_ct.c b/drivers/video/aty/mach64_ct.c
index f3b487b..1fdcfdb 100644
--- a/drivers/video/aty/mach64_ct.c
+++ b/drivers/video/aty/mach64_ct.c
@@ -598,7 +598,6 @@ static void aty_resume_pll_ct(const struct fb_info *info,
struct atyfb_par *par = info->par;
if (par->mclk_per != par->xclk_per) {
- int i;
/*
* This disables the sclk, crashes the computer as reported:
* aty_st_pll_ct(SPLL_CNTL2, 3, info);
@@ -614,7 +613,7 @@ static void aty_resume_pll_ct(const struct fb_info *info,
* helps for Rage Mobilities that sometimes crash when
* we switch to sclk. (Daniel Mantione, 13-05-2003)
*/
- for (i=0;i<=0x1ffff;i++);
+ udelay(500);
}
aty_st_pll_ct(PLL_REF_DIV, pll->ct.pll_ref_div, par);