From: David Miller Date: Mon, 5 Mar 2007 09:35:36 +0000 (-0800) Subject: [PATCH] video/aty/mach64_ct.c: fix bogus delay loop X-Git-Tag: v2.6.21-rc3~59 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8690ba446defe2e2b81803756c099d2943dfd5fd;p=linux-2.6 [PATCH] video/aty/mach64_ct.c: fix bogus delay loop 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 Signed-off-by: Linus Torvalds --- diff --git a/drivers/video/aty/mach64_ct.c b/drivers/video/aty/mach64_ct.c index f3b487b871..1fdcfdbf66 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);