Patch "drm/amdgpu: check before checking pci bridge registers" has been added to the 4.2-stable tree

Patch "drm/amdgpu: check before checking pci bridge registers" has been added to the 4.2-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    drm/amdgpu: check before checking pci bridge registers

to the 4.2-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-amdgpu-check-before-checking-pci-bridge-registers.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From e79d5c0870eedce94e5f5a2ffab30511e48fa144 Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher@amd.com>
Date: Tue, 6 Oct 2015 09:38:45 -0400
Subject: drm/amdgpu: check before checking pci bridge registers
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Alex Deucher <alexander.deucher@amd.com>

commit e79d5c0870eedce94e5f5a2ffab30511e48fa144 upstream.

Make sure we are not the root device before attempting to
read the pcie bridge registers to check the pcie gen speeed.

Fixes a crash when the device is passed through to a VM.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/amd/amdgpu/cik.c |    3 +++
 drivers/gpu/drm/amd/amdgpu/vi.c  |    3 +++
 2 files changed, 6 insertions(+)

--- a/drivers/gpu/drm/amd/amdgpu/cik.c
+++ b/drivers/gpu/drm/amd/amdgpu/cik.c
@@ -1565,6 +1565,9 @@ static void cik_pcie_gen3_enable(struct
 	int ret, i;
 	u16 tmp16;
 
+	if (pci_is_root_bus(adev->pdev->bus))
+		return;
+
 	if (amdgpu_pcie_gen2 == 0)
 		return;
 
--- a/drivers/gpu/drm/amd/amdgpu/vi.c
+++ b/drivers/gpu/drm/amd/amdgpu/vi.c
@@ -968,6 +968,9 @@ static void vi_pcie_gen3_enable(struct a
 	u32 mask;
 	int ret;
 
+	if (pci_is_root_bus(adev->pdev->bus))
+		return;
+
 	if (amdgpu_pcie_gen2 == 0)
 		return;
 


Patches currently in stable-queue which might be from alexander.deucher@amd.com are

queue-4.2/drm-amdgpu-keep-the-pflip-interrupts-always-enabled-v7.patch
queue-4.2/drm-amdgpu-fix-num_crtc-on-cz.patch
queue-4.2/drm-amdgpu-check-before-checking-pci-bridge-registers.patch
queue-4.2/drm-radeon-add-pm-sysfs-files-late.patch
queue-4.2/drm-amdgpu-add-pm-sysfs-files-late.patch