3.16.82-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Sam Bobroff <sbobroff@xxxxxxxxxxxxx> commit 62d91dd2851e8ae2ca552f1b090a3575a4edf759 upstream. The INTERRUPT_CNTL2 register expects a valid DMA address, but is currently set with a GPU MC address. This can cause problems on systems that detect the resulting DMA read from an invalid address (found on a Power8 guest). Instead, use the DMA address of the dummy page because it will always be safe. Fixes: d8f60cfc9345 ("drm/radeon/kms: Add support for interrupts on r6xx/r7xx chips (v3)") Fixes: 25a857fbe973 ("drm/radeon/kms: add support for interrupts on SI") Fixes: a59781bbe528 ("drm/radeon: add support for interrupts on CIK (v5)") Signed-off-by: Sam Bobroff <sbobroff@xxxxxxxxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- drivers/gpu/drm/radeon/cik.c | 4 ++-- drivers/gpu/drm/radeon/r600.c | 4 ++-- drivers/gpu/drm/radeon/si.c | 4 ++-- 3 files changed, 6 insertions(+), 6 deletions(-) --- a/drivers/gpu/drm/radeon/cik.c +++ b/drivers/gpu/drm/radeon/cik.c @@ -6875,8 +6875,8 @@ static int cik_irq_init(struct radeon_de } /* setup interrupt control */ - /* XXX this should actually be a bus address, not an MC address. same on older asics */ - WREG32(INTERRUPT_CNTL2, rdev->ih.gpu_addr >> 8); + /* set dummy read address to dummy page address */ + WREG32(INTERRUPT_CNTL2, rdev->dummy_page.addr >> 8); interrupt_cntl = RREG32(INTERRUPT_CNTL); /* IH_DUMMY_RD_OVERRIDE=0 - dummy read disabled with msi, enabled without msi * IH_DUMMY_RD_OVERRIDE=1 - dummy read controlled by IH_DUMMY_RD_EN --- a/drivers/gpu/drm/radeon/r600.c +++ b/drivers/gpu/drm/radeon/r600.c @@ -3427,8 +3427,8 @@ int r600_irq_init(struct radeon_device * } /* setup interrupt control */ - /* set dummy read address to ring address */ - WREG32(INTERRUPT_CNTL2, rdev->ih.gpu_addr >> 8); + /* set dummy read address to dummy page address */ + WREG32(INTERRUPT_CNTL2, rdev->dummy_page.addr >> 8); interrupt_cntl = RREG32(INTERRUPT_CNTL); /* IH_DUMMY_RD_OVERRIDE=0 - dummy read disabled with msi, enabled without msi * IH_DUMMY_RD_OVERRIDE=1 - dummy read controlled by IH_DUMMY_RD_EN --- a/drivers/gpu/drm/radeon/si.c +++ b/drivers/gpu/drm/radeon/si.c @@ -5749,8 +5749,8 @@ static int si_irq_init(struct radeon_dev } /* setup interrupt control */ - /* set dummy read address to ring address */ - WREG32(INTERRUPT_CNTL2, rdev->ih.gpu_addr >> 8); + /* set dummy read address to dummy page address */ + WREG32(INTERRUPT_CNTL2, rdev->dummy_page.addr >> 8); interrupt_cntl = RREG32(INTERRUPT_CNTL); /* IH_DUMMY_RD_OVERRIDE=0 - dummy read disabled with msi, enabled without msi * IH_DUMMY_RD_OVERRIDE=1 - dummy read controlled by IH_DUMMY_RD_EN