From 7c81e0205b52824a7c21fe873ae6a3780435a309 Mon Sep 17 00:00:00 2001 From: Ben Crocker Date: Thu, 22 Feb 2018 17:52:19 -0500 Subject: [PATCH] drm/radeon: insist on 32-bit DMA for Cedar on PPC64/PPC64LE 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 5940d76a7463b52630b4ad1a6aedc66a08ab97e4 (Russell Currey) and 0c703bca39114cc8334ea117e512a5b06a2f67f4 (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 Signed-off-by: Alex Deucher Cc: stable@vger.kernel.org --- drivers/gpu/drm/radeon/radeon_device.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c index 7f40c6f7c4dd8..e415d2c097a70 100644 --- a/drivers/gpu/drm/radeon/radeon_device.c +++ b/drivers/gpu/drm/radeon/radeon_device.c @@ -1366,6 +1366,10 @@ int radeon_device_init(struct radeon_device *rdev, 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)); -- 2.39.5