Re: [PATCH v2] drm/tegra: Stop using iommu_present()

On 4/11/22 16:46, Robin Murphy wrote:

@@ -1092,6 +1092,19 @@ static bool host1x_drm_wants_iommu(struct host1x_device *dev) struct host1x *host1x = dev_get_drvdata(dev->dev.parent); struct iommu_domain *domain;

• /* For starters, this is moot if no IOMMU is available */
• if (!device_iommu_mapped(&dev->dev))

• return false;
  

Unfortunately this returns false on T30 with enabled IOMMU because we don't use IOMMU for Host1x on T30 [1] to optimize performance. We can't change it until we will update drivers to support Host1x-dedicated buffers.

[1] https://elixir.bootlin.com/linux/latest/source/drivers/gpu/host1x/dev.c#L258