Messages in this thread | | | Date | Sat, 14 Nov 2020 17:21:59 +0100 | From | Christoph Hellwig <> | Subject | Re: [RESEND PATCH v2 3/5] drm/msm: call dma_direct_bypass() |
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On Sat, Nov 14, 2020 at 10:17:11AM -0500, Jonathan Marek wrote: > Always use direct dma ops and no swiotlb. > > Note: arm-smmu-qcom already avoids creating iommu dma ops, but not > everything uses arm-smmu-qcom and this also sets the dma mask. > > Signed-off-by: Jonathan Marek <jonathan@marek.ca> > --- > drivers/gpu/drm/msm/Kconfig | 1 + > drivers/gpu/drm/msm/msm_drv.c | 8 +++++--- > 2 files changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/msm/Kconfig b/drivers/gpu/drm/msm/Kconfig > index e5816b498494..07c50405970a 100644 > --- a/drivers/gpu/drm/msm/Kconfig > +++ b/drivers/gpu/drm/msm/Kconfig > @@ -20,6 +20,7 @@ config DRM_MSM > select SND_SOC_HDMI_CODEC if SND_SOC > select SYNC_FILE > select PM_OPP > + select DMA_OPS_BYPASS > help > DRM/KMS driver for MSM/snapdragon. > > diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c > index 49685571dc0e..bae48afca82e 100644 > --- a/drivers/gpu/drm/msm/msm_drv.c > +++ b/drivers/gpu/drm/msm/msm_drv.c > @@ -6,6 +6,7 @@ > */ > > #include <linux/dma-mapping.h> > +#include <linux/dma-direct.h> > #include <linux/kthread.h> > #include <linux/uaccess.h> > #include <uapi/linux/sched/types.h> > @@ -1288,10 +1289,11 @@ static int msm_pdev_probe(struct platform_device *pdev) > if (ret) > goto fail; > > - /* on all devices that I am aware of, iommu's which can map > - * any address the cpu can see are used: > + /* always use direct dma ops and no swiotlb
Again, and implementation detail. Comments should not explain details obvious from the code (especially layers away) but the intent.
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