Hi Greg,
On Wed, Jul 15, 2020 at 3:11 AM Greg Kroah-Hartman gregkh@linuxfoundation.org wrote:
From: Maxime Ripard maxime@cerno.tech
[ Upstream commit 842ec61f4006a6477a9deaedd69131e9f46e4cb5 ]
The main DRM device is actually a virtual device so it doesn't have the iommus property, which is instead on the DMA masters, in this case the mixers.
The iommu driver and DT changes were added in v5.8-rc1. IMO There is no point in backporting this patch to any stable kernel.
ChenYu
Add a call to of_dma_configure with the mixers DT node but on the DRM virtual device to configure it in the same way than the mixers.
Reviewed-by: Paul Kocialkowski paul.kocialkowski@bootlin.com Signed-off-by: Maxime Ripard maxime@cerno.tech Link: https://patchwork.freedesktop.org/patch/msgid/9a4daf438dd3f2fe07afb23688bfb7... (cherry picked from commit b718102dbdfd0285ad559687a30e27cc9124e592) [Maxime: Applied to -fixes since it missed the merge window and display is broken without it] Signed-off-by: Maxime Ripard maxime@cerno.tech Signed-off-by: Sasha Levin sashal@kernel.org
drivers/gpu/drm/sun4i/sun8i_mixer.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
diff --git a/drivers/gpu/drm/sun4i/sun8i_mixer.c b/drivers/gpu/drm/sun4i/sun8i_mixer.c index 18b4881f44814..e24f225d80f1f 100644 --- a/drivers/gpu/drm/sun4i/sun8i_mixer.c +++ b/drivers/gpu/drm/sun4i/sun8i_mixer.c @@ -452,6 +452,19 @@ static int sun8i_mixer_bind(struct device *dev, struct device *master, mixer->engine.ops = &sun8i_engine_ops; mixer->engine.node = dev->of_node;
if (of_find_property(dev->of_node, "iommus", NULL)) {/** This assume we have the same DMA constraints for* all our the mixers in our pipeline. This sounds* bad, but it has always been the case for us, and* DRM doesn't do per-device allocation either, so we* would need to fix DRM first...*/ret = of_dma_configure(drm->dev, dev->of_node, true);if (ret)return ret;}/* * While this function can fail, we shouldn't do anything * if this happens. Some early DE2 DT entries don't provide-- 2.25.1