From 5349ef3127c77075ff70b2014f17ae0fbcaaf199 Mon Sep 17 00:00:00 2001
From: Clemens Ladisch <clemens@ladisch.de>
Date: Wed, 4 Nov 2009 09:42:52 +0100
Subject: [PATCH] drm/fb: fix FBIOGET/PUT_VSCREENINFO pixel clock handling
When the framebuffer driver does not publish detailed timing information
for the current video mode, the correct value for the pixclock field is
zero, not -1.
Since pixclock is actually unsigned, the value -1 would be interpreted
as 4294967295 picoseconds (i.e., about 4 milliseconds) by
register_framebuffer() and userspace programs.
This patch allows X.org's fbdev driver to work.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Tested-by: Paulius Zaleckas <paulius.zaleckas@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
---
drivers/gpu/drm/drm_fb_helper.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index dc8e374a0b55e..65ef011fa8ba0 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -599,7 +599,7 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
struct drm_framebuffer *fb = fb_helper->fb;
int depth;
- if (var->pixclock == -1 || !var->pixclock)
+ if (var->pixclock != 0)
return -EINVAL;
/* Need to resize the fb object !!! */
@@ -691,7 +691,7 @@ int drm_fb_helper_set_par(struct fb_info *info)
int ret;
int i;
- if (var->pixclock != -1) {
+ if (var->pixclock != 0) {
DRM_ERROR("PIXEL CLCOK SET\n");
return -EINVAL;
}
@@ -904,7 +904,7 @@ int drm_fb_helper_single_fb_probe(struct drm_device *dev,
fb_helper->fb = fb;
if (new_fb) {
- info->var.pixclock = -1;
+ info->var.pixclock = 0;
if (register_framebuffer(info) < 0)
return -EINVAL;
} else {
--
GitLab