[ 3.5.y.z extended stable ] Patch "drm/mgag200: Reject modes that are too big for VRAM" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    drm/mgag200: Reject modes that are too big for VRAM

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From ef94f2713b7a84b790463f93421f8e204a2eb099 Mon Sep 17 00:00:00 2001
From: Christopher Harvey <charvey at matrox.com>
Date: Tue, 26 Feb 2013 10:55:44 -0500
Subject: [PATCH] drm/mgag200: Reject modes that are too big for VRAM

commit 0ba53171583f86bbcbba951fe172982f7fc3761c upstream.

A monitor or a user could request a resolution greater than the
available VRAM for the backing framebuffer. This change checks the
required framebuffer size against the max VRAM size and rejects modes
if they are too big. This change can also remove a mode request passed
in via the video= parameter.

Signed-off-by: Christopher Harvey <charvey at matrox.com>
Signed-off-by: Dave Airlie <airlied at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/gpu/drm/mgag200/mgag200_mode.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
index 4e48f91..6356ea1 100644
--- a/drivers/gpu/drm/mgag200/mgag200_mode.c
+++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
@@ -1423,6 +1423,14 @@ static int mga_vga_get_modes(struct drm_connector *connector)
 static int mga_vga_mode_valid(struct drm_connector *connector,
 				 struct drm_display_mode *mode)
 {
+	struct drm_device *dev = connector->dev;
+	struct mga_device *mdev = (struct mga_device*)dev->dev_private;
+	struct mga_fbdev *mfbdev = mdev->mfbdev;
+	struct drm_fb_helper *fb_helper = &mfbdev->helper;
+	struct drm_fb_helper_connector *fb_helper_conn = NULL;
+	int bpp = 32;
+	int i = 0;
+
 	/* FIXME: Add bandwidth and g200se limitations */

 	if (mode->crtc_hdisplay > 2048 || mode->crtc_hsync_start > 4096 ||
@@ -1432,6 +1440,25 @@ static int mga_vga_mode_valid(struct drm_connector *connector,
 		return MODE_BAD;
 	}

+	/* Validate the mode input by the user */
+	for (i = 0; i < fb_helper->connector_count; i++) {
+		if (fb_helper->connector_info[i]->connector == connector) {
+			/* Found the helper for this connector */
+			fb_helper_conn = fb_helper->connector_info[i];
+			if (fb_helper_conn->cmdline_mode.specified) {
+				if (fb_helper_conn->cmdline_mode.bpp_specified) {
+					bpp = fb_helper_conn->cmdline_mode.bpp;
+				}
+			}
+		}
+	}
+
+	if ((mode->hdisplay * mode->vdisplay * (bpp/8)) > mdev->mc.vram_size) {
+		if (fb_helper_conn)
+			fb_helper_conn->cmdline_mode.specified = false;
+		return MODE_BAD;
+	}
+
 	return MODE_OK;
 }

--
1.8.1.2