linux-kernel - [PATCH] drm/fb-helper: Allow var->x/yres(

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Date:   Thu, 23 Mar 2017 17:53:26 +0900
From:   Michel Dänzer <michel@...nzer.net>
To:     Stefan Agner <stefan@...er.ch>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Ville Syrjälä 
        <ville.syrjala@...ux.intel.com>,
        Daniel Stone <daniel@...ishbar.org>
Subject: [PATCH] drm/fb-helper: Allow var->x/yres(_virtual) < fb->width/height again

From: Michel Dänzer <michel.daenzer@....com>

Otherwise this can also prevent modesets e.g. for switching VTs, when
multiple monitors with different native resolutions are connected.

The depths must match though, so keep the != test for that.

Also update the DRM_DEBUG output to be slightly more accurate, this
doesn't only affect requests from userspace.

Bugzilla: https://bugs.freedesktop.org/99841
Fixes: 865afb11949e ("drm/fb-helper: reject any changes to the fbdev")
Signed-off-by: Michel Dänzer <michel.daenzer@....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 f6d4d9700734..324a688b3f30 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1260,9 +1260,9 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
 	 * 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) {
-		DRM_DEBUG("fb userspace requested width/height/bpp different than current fb "
+	    var->xres > fb->width || var->yres > fb->height ||
+	    var->xres_virtual > fb->width || var->yres_virtual > fb->height) {
+		DRM_DEBUG("fb requested width/height/bpp can't fit in current fb "
 			  "request %dx%d-%d (virtual %dx%d) > %dx%d-%d\n",
 			  var->xres, var->yres, var->bits_per_pixel,
 			  var->xres_virtual, var->yres_virtual,
-- 
2.11.0