This is a note to let you know that I've just added the patch titled
drm/radeon: insist on 32-bit DMA for Cedar on PPC64/PPC64LE
to the 4.15-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-insist-on-32-bit-dma-for-cedar-on-ppc64-ppc64le.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2c83029cda55a5e7665c7c6326909427d6a01350 Mon Sep 17 00:00:00 2001
From: Ben Crocker <bcrocker@xxxxxxxxxx>
Date: Thu, 22 Feb 2018 17:52:19 -0500
Subject: drm/radeon: insist on 32-bit DMA for Cedar on PPC64/PPC64LE
From: Ben Crocker <bcrocker@xxxxxxxxxx>
commit 2c83029cda55a5e7665c7c6326909427d6a01350 upstream.
In radeon_device_init, set the need_dma32 flag for Cedar chips
(e.g. FirePro 2270). This fixes, or at least works around, a bug
on PowerPC exposed by last year's commits
8e3f1b1d8255105f31556aacf8aeb6071b00d469 (Russell Currey)
and
253fd51e2f533552ae35a0c661705da6c4842c1b (Alistair Popple)
which enabled the 64-bit DMA iommu bypass.
This caused the device to freeze, in some cases unrecoverably, and is
the subject of several bug reports internal to Red Hat.
Signed-off-by: Ben Crocker <bcrocker@xxxxxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/radeon/radeon_device.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1397,6 +1397,10 @@ int radeon_device_init(struct radeon_dev
if ((rdev->flags & RADEON_IS_PCI) &&
(rdev->family <= CHIP_RS740))
rdev->need_dma32 = true;
+#ifdef CONFIG_PPC64
+ if (rdev->family == CHIP_CEDAR)
+ rdev->need_dma32 = true;
+#endif
dma_bits = rdev->need_dma32 ? 32 : 40;
r = pci_set_dma_mask(rdev->pdev, DMA_BIT_MASK(dma_bits));
Patches currently in stable-queue which might be from bcrocker@xxxxxxxxxx are
queue-4.15/drm-radeon-insist-on-32-bit-dma-for-cedar-on-ppc64-ppc64le.patch