From b586640141ab5f4ab3b194419bc2c0f039e91dbc Mon Sep 17 00:00:00 2001 From: Paul Menzel Date: Tue, 16 Jun 2009 15:34:37 -0700 Subject: [PATCH] intelfb: fix a bug when changing video timing When changing video timing dynamically via fbset the screen sporadically is rendered black. With the attached fix which disables VCO prior to timing register change the problem disappears. I had a look at the Xserver register setup code. Here the VCO is disabled in the same way [1]. This patch is taken from vga-sync-field version 0.0.11 [2][3]. [1] http://cgit.freedesktop.org/xorg/driver/xf86-video-intel/tree/src/i830_= driver.c [2] http://lowbyte.de/vga-sync-fields/vga-sync-fields-0.0.11.tgz [3] http://easy-vdr.de/git?p=frc.git/.git;a=commit;h=dcc3b863e5a663652587619c357bd20075af6896 2587619c357bd20075af6896 Signed-off-by: Thomas Hilber Signed-off-by: Paul Menzel Cc: Krzysztof Helt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/video/intelfb/intelfbdrv.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/video/intelfb/intelfbdrv.c b/drivers/video/intelfb/intelfbdrv.c index ace14fe02fc4..0cafd642fbc0 100644 --- a/drivers/video/intelfb/intelfbdrv.c +++ b/drivers/video/intelfb/intelfbdrv.c @@ -1365,6 +1365,11 @@ static int intelfb_set_par(struct fb_info *info) DBG_MSG("intelfb_set_par (%dx%d-%d)\n", info->var.xres, info->var.yres, info->var.bits_per_pixel); + /* + * Disable VCO prior to timing register change. + */ + OUTREG(DPLL_A, INREG(DPLL_A) & ~DPLL_VCO_ENABLE); + intelfb_blank(FB_BLANK_POWERDOWN, info); if (ACCEL(dinfo, info)) -- 2.30.2