On Thu, Mar 16, 2017 at 06:55:53PM +0900, Michel Dänzer wrote:
From: Michel Dänzer michel.daenzer@amd.com
Otherwise this can also prevent modesets e.g. for switching VTs.
FB_MISC_USER_EVENT is set when the request originates from userspace, which is what we're interested in here according to the DRM_DEBUG output.
So why is the kernel allowed to violate this?
The checks look somewhat bogus to me anyway. The 'virtual size == fb size' check makes some kind of sense. Although I don't see why the virtual resolution couldn't be smaller than the fb size. But requiring that the visible resolutionn matches the fb size as well definitely seems wrong.
Maybe Cc whoever broke this?
Bugzilla: https://bugs.freedesktop.org/99841 Fixes: 865afb11949e ("drm/fb-helper: reject any changes to the fbdev") Signed-off-by: Michel Dänzer michel.daenzer@amd.com
I'm not entirely sure why the values can not match for a VT switch. If anybody thinks this just papers over the real issue, please speak up.
drivers/gpu/drm/drm_fb_helper.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index f6d4d9700734..9663f3b8f287 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -1259,9 +1259,10 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var, * Changes struct fb_var_screeninfo are currently not pushed back * to KMS, hence fail if different settings are requested. */
- if (var->bits_per_pixel != fb->format->cpp[0] * 8 ||
var->xres != fb->width || var->yres != fb->height ||var->xres_virtual != fb->width || var->yres_virtual != fb->height) {
- if ((info->flags & FBINFO_MISC_USEREVENT) &&
(var->bits_per_pixel != fb->format->cpp[0] * 8 ||var->xres != fb->width || var->yres != fb->height ||var->xres_virtual != fb->width || var->yres_virtual != fb->height)) {-- 2.11.0
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