Re: [PATCH v2 0/3] drm: panfrost: Coherency support

Re: [PATCH v2 0/3] drm: panfrost: Coherency support

[Robin Murphy]

Hi Greg,

On 2020-09-22 15:16, Robin Murphy wrote:
> Hi all,
> 
> Here's a quick v2 with the tags so far picked up and some inline
> commentary about the shareability domains for the pagetable code.
> 
> Robin.
> 
> 
> Robin Murphy (3):
>    iommu/io-pgtable-arm: Support coherency for Mali LPAE
>    drm/panfrost: Support cache-coherent integrations
>    arm64: dts: meson: Describe G12b GPU as coherent

Please would you consider applying these patches to 5.10 stable? The 
mainline commit IDs are now:

728da60da7c1 iommu/io-pgtable-arm: Support coherency for Mali LPAE
268af50f38b1 drm/panfrost: Support cache-coherent integrations
03544505cb10 arm64: dts: meson: Describe G12b GPU as coherent

and I've checked that they cherry-pick to the current 5.10.y branch 
(5.10.12) cleanly.

Amlogic-based boards that require this support are quite popular, and 
end-users are now starting to run into the weird behaviour that ensues 
without it, which is all to easy to misattribute to the userspace driver 
in Mesa, e.g. [1],[2]. Fortunately 5.10 also happens to be the first 
kernel version to start probing the particular GPU models on these SoCs 
anyway, and I'm not aware of any other significant systems that are 
affected, so I don't believe we will need to worry about any other 
stable versions.

Thanks,
Robin.

[1] https://gitlab.freedesktop.org/mesa/mesa/-/issues/4157
[2] https://gitlab.freedesktop.org/mesa/mesa/-/issues/4160

> 
>   arch/arm64/boot/dts/amlogic/meson-g12b.dtsi |  4 ++++
>   drivers/gpu/drm/panfrost/panfrost_device.h  |  1 +
>   drivers/gpu/drm/panfrost/panfrost_drv.c     |  2 ++
>   drivers/gpu/drm/panfrost/panfrost_gem.c     |  2 ++
>   drivers/gpu/drm/panfrost/panfrost_mmu.c     |  1 +
>   drivers/iommu/io-pgtable-arm.c              | 11 ++++++++++-
>   6 files changed, 20 insertions(+), 1 deletion(-)
> 

Re: [PATCH v2 0/3] drm: panfrost: Coherency support

[Greg KH]

On Wed, Feb 03, 2021 at 12:38:09PM +0000, Robin Murphy wrote:
> Hi Greg,
> 
> On 2020-09-22 15:16, Robin Murphy wrote:
> > Hi all,
> > 
> > Here's a quick v2 with the tags so far picked up and some inline
> > commentary about the shareability domains for the pagetable code.
> > 
> > Robin.
> > 
> > 
> > Robin Murphy (3):
> >    iommu/io-pgtable-arm: Support coherency for Mali LPAE
> >    drm/panfrost: Support cache-coherent integrations
> >    arm64: dts: meson: Describe G12b GPU as coherent
> 
> Please would you consider applying these patches to 5.10 stable? The
> mainline commit IDs are now:
> 
> 728da60da7c1 iommu/io-pgtable-arm: Support coherency for Mali LPAE
> 268af50f38b1 drm/panfrost: Support cache-coherent integrations
> 03544505cb10 arm64: dts: meson: Describe G12b GPU as coherent
> 
> and I've checked that they cherry-pick to the current 5.10.y branch
> (5.10.12) cleanly.
> 
> Amlogic-based boards that require this support are quite popular, and
> end-users are now starting to run into the weird behaviour that ensues
> without it, which is all to easy to misattribute to the userspace driver in
> Mesa, e.g. [1],[2]. Fortunately 5.10 also happens to be the first kernel
> version to start probing the particular GPU models on these SoCs anyway, and
> I'm not aware of any other significant systems that are affected, so I don't
> believe we will need to worry about any other stable versions.

That's small enough, now queued up, thanks.

greg k-h