From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sinan Kaya Subject: [PATCH V2] drm/amdgpu: limit DMA size to PAGE_SIZE for scatter-gather buffers Date: Tue, 10 Apr 2018 16:59:55 -0400 Message-ID: <1523394001-4615-1-git-send-email-okaya@codeaurora.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-kernel-owner@vger.kernel.org To: amd-gfx@lists.freedesktop.org, timur@codeaurora.org, sulrich@codeaurora.org Cc: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sinan Kaya , Alex Deucher , =?UTF-8?q?Christian=20K=C3=B6nig?= , "David (ChunMing) Zhou" , David Airlie , Felix Kuehling , Monk Liu , Roger He , Jim Qu , Emily Deng , Feifei Xu , Huang Rui , Tom St Denis , David Panariti , "open list:DRM DRIVERS" , open list List-Id: linux-arm-msm@vger.kernel.org Code is expecing to observe the same number of buffers returned from dma_map_sg() function compared to sg_alloc_table_from_pages(). This doesn't hold true universally especially for systems with IOMMU. IOMMU driver tries to combine buffers into a single DMA address as much as it can. The right thing is to tell the DMA layer how much combining IOMMU can do. Signed-off-by: Sinan Kaya --- drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c | 2 +- drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c | 1 + drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c | 1 + drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 1 + 4 files changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c index 8e28270..1b031eb 100644 --- a/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c @@ -851,7 +851,7 @@ static int gmc_v6_0_sw_init(void *handle) pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32)); dev_warn(adev->dev, "amdgpu: No coherent DMA available.\n"); } - + dma_set_max_seg_size(adev->dev, PAGE_SIZE); r = gmc_v6_0_init_microcode(adev); if (r) { dev_err(adev->dev, "Failed to load mc firmware!\n"); diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c index 86e9d682..0a4b2cc1 100644 --- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c @@ -999,6 +999,7 @@ static int gmc_v7_0_sw_init(void *handle) pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32)); pr_warn("amdgpu: No coherent DMA available\n"); } + dma_set_max_seg_size(adev->dev, PAGE_SIZE); r = gmc_v7_0_init_microcode(adev); if (r) { diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c index 9a813d8..b171529 100644 --- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c @@ -1096,6 +1096,7 @@ static int gmc_v8_0_sw_init(void *handle) pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32)); pr_warn("amdgpu: No coherent DMA available\n"); } + dma_set_max_seg_size(adev->dev, PAGE_SIZE); r = gmc_v8_0_init_microcode(adev); if (r) { diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c index 3b7e7af..36e658ab 100644 --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c @@ -855,6 +855,7 @@ static int gmc_v9_0_sw_init(void *handle) pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32)); printk(KERN_WARNING "amdgpu: No coherent DMA available.\n"); } + dma_set_max_seg_size(adev->dev, PAGE_SIZE); r = gmc_v9_0_mc_init(adev); if (r) -- 2.7.4