Borken IOMMU+i915

Borken IOMMU+i915

[Peter.Chubb-RgbkMxAV74wUb6iz2VnApA]

Hi Lu,
	In recent kernels, i915 graphics with intel_iommu=on has been
	giving me a blank screen.

	git bisect points at your patch ab96746aaa34
	"iommu/vt-d: Clean up pasid quirk for pre-production devices"

	Either one of the pre-production devices made it into my Dell
	laptop, or there's something else wrong with the patch.

	Reverting that patch gives me text console and X11 graphics;
	keeping it in yields a blank screen on boot.

	My laptop is a Dell  Inc. Precision 7710/0PMJX2, BIOS 1.15.4 12/08/2017
	CPU is  Intel(R) Core(TM) i7-6920HQ CPU @ 2.90GHz
	(family: 0x6, model: 0x5e, stepping: 0x3)

Peter C
-- 
Dr Peter Chubb         Tel: +61 2 9490 5852      http://ts.data61.csiro.au/
Trustworthy Systems Group                     Data61, CSIRO (formerly NICTA)

Re: Borken IOMMU+i915

[Lu Baolu]

Hi Peter,

There is already a patch to revert that broken patch.

https://patchwork.kernel.org/patch/10513017/

Best regards,
Lu Baolu

On 07/15/2018 04:29 PM, Peter.Chubb-RgbkMxAV74wUb6iz2VnApA@public.gmane.org wrote:
> Hi Lu,
> 	In recent kernels, i915 graphics with intel_iommu=on has been
> 	giving me a blank screen.
>
> 	git bisect points at your patch ab96746aaa34
> 	"iommu/vt-d: Clean up pasid quirk for pre-production devices"
>
> 	Either one of the pre-production devices made it into my Dell
> 	laptop, or there's something else wrong with the patch.
>
> 	Reverting that patch gives me text console and X11 graphics;
> 	keeping it in yields a blank screen on boot.
>
> 	My laptop is a Dell  Inc. Precision 7710/0PMJX2, BIOS 1.15.4 12/08/2017
> 	CPU is  Intel(R) Core(TM) i7-6920HQ CPU @ 2.90GHz
> 	(family: 0x6, model: 0x5e, stepping: 0x3)
>
> Peter C