[3.5.y.z extended stable] Patch "drm/radeon: fixup bad vram size on SI" 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/radeon: fixup bad vram size on SI

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 417ee49a4208d45b82f96c5c9a402296f20ad78e Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher at amd.com>
Date: Tue, 3 Dec 2013 09:24:30 -0500
Subject: drm/radeon: fixup bad vram size on SI

commit 0ca223b029a261e82fb2f50c52eb85d510f4260e upstream.

Some boards seem to have garbage in the upper
16 bits of the vram size register.  Check for
this and clamp the size properly.  Fixes
boards reporting bogus amounts of vram.

Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/gpu/drm/radeon/si.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
index 9987345..b7be000 100644
--- a/drivers/gpu/drm/radeon/si.c
+++ b/drivers/gpu/drm/radeon/si.c
@@ -2325,8 +2325,15 @@ static int si_mc_init(struct radeon_device *rdev)
 	rdev->mc.aper_base = pci_resource_start(rdev->pdev, 0);
 	rdev->mc.aper_size = pci_resource_len(rdev->pdev, 0);
 	/* size in MB on si */
-	rdev->mc.mc_vram_size = RREG32(CONFIG_MEMSIZE) * 1024ULL * 1024ULL;
-	rdev->mc.real_vram_size = RREG32(CONFIG_MEMSIZE) * 1024ULL * 1024ULL;
+	tmp = RREG32(CONFIG_MEMSIZE);
+	/* some boards may have garbage in the upper 16 bits */
+	if (tmp & 0xffff0000) {
+		DRM_INFO("Probable bad vram size: 0x%08x\n", tmp);
+		if (tmp & 0xffff)
+			tmp &= 0xffff;
+	}
+	rdev->mc.mc_vram_size = tmp * 1024ULL * 1024ULL;
+	rdev->mc.real_vram_size = rdev->mc.mc_vram_size;
 	rdev->mc.visible_vram_size = rdev->mc.aper_size;
 	si_vram_gtt_location(rdev, &rdev->mc);
 	radeon_update_bandwidth_info(rdev);
--
1.8.3.2