Patch "drm/radeon: Don't flush the GART TLB if rdev->gart.ptr == NULL" has been added to the 4.1-stable tree

[<gregkh@linuxfoundation.org>]

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

    drm/radeon: Don't flush the GART TLB if rdev->gart.ptr == NULL

to the 4.1-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-radeon-don-t-flush-the-gart-tlb-if-rdev-gart.ptr-null.patch
and it can be found in the queue-4.1 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 233709d2cd6bbaaeda0aeb8d11f6ca7f98563b39 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <michel.daenzer@amd.com>
Date: Fri, 3 Jul 2015 10:02:27 +0900
Subject: drm/radeon: Don't flush the GART TLB if rdev->gart.ptr == NULL
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Content-Type: text/plain; charset=UTF-8
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From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <michel.daenzer@amd.com>

commit 233709d2cd6bbaaeda0aeb8d11f6ca7f98563b39 upstream.

This can be the case when the GPU is powered off, e.g. via vgaswitcheroo
or runpm. When the GPU is powered up again, radeon_gart_table_vram_pin
flushes the TLB after setting rdev->gart.ptr to non-NULL.

Fixes panic on powering off R7xx GPUs.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61529
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/radeon/radeon_gart.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- a/drivers/gpu/drm/radeon/radeon_gart.c
+++ b/drivers/gpu/drm/radeon/radeon_gart.c
@@ -260,8 +260,10 @@ void radeon_gart_unbind(struct radeon_de
 			}
 		}
 	}
-	mb();
-	radeon_gart_tlb_flush(rdev);
+	if (rdev->gart.ptr) {
+		mb();
+		radeon_gart_tlb_flush(rdev);
+	}
 }
 
 /**
@@ -306,8 +308,10 @@ int radeon_gart_bind(struct radeon_devic
 			page_base += RADEON_GPU_PAGE_SIZE;
 		}
 	}
-	mb();
-	radeon_gart_tlb_flush(rdev);
+	if (rdev->gart.ptr) {
+		mb();
+		radeon_gart_tlb_flush(rdev);
+	}
 	return 0;
 }
 


Patches currently in stable-queue which might be from michel.daenzer@amd.com are

queue-4.1/drm-radeon-handle-irqs-only-based-on-irq-ring-not-irq-status-regs.patch
queue-4.1/drm-radeon-clean-up-reference-counting-and-pinning-of-the-cursor-bos.patch
queue-4.1/drm-radeon-unpin-cursor-bos-on-suspend-and-pin-them-again-on-resume-v2.patch
queue-4.1/drm-radeon-don-t-flush-the-gart-tlb-if-rdev-gart.ptr-null.patch