Re: [PATCH RESEND 0/2] media: rockchip: rga: Add rk3568 support

On 2023-05-22 11:29, Michael Tretter wrote:

On Sun, 21 May 2023 21:32:51 +0200, Diederik de Haas wrote:

quoted

On Sunday, 21 May 2023 12:44:58 CEST Heiko Stuebner wrote:

quoted

On Fri, 20 Jan 2023 10:14:21 +0100, Michael Tretter wrote:

quoted

The RGA2 on the Rockchip rk3568 is the same core as the RGA2 on the
Rockchip rk3288.

This series adds the necessary device tree binding and node in the device
tree to enable the RGA2 on the Rockchip rk3568.

I tested the driver with the GStreamer v4l2convert element on a Rock3
Model A board.

[...]

Applied, thanks!

[1/2] media: dt-bindings: media: rockchip-rga: add rockchip,rk3568-rga
       commit: 9b12ceb5a80d1fb45d293265de100e33b5843943
[2/2] arm64: dts: rockchip: Add RGA2 support to rk356x
       commit: 0c3391f8bb06b744df521651534cd99e3d77e0a8

https://lore.kernel.org/all/TY3P286MB26115F60D273E840D36A610598CA9@TY3P286MB2611.JPNP286.PROD.OUTLOOK.COM/ (local)

indicated that there was a problem with device >= 4GB (RAM?):

quoted

Since we have the over-4GB problem now, should we mark this problem as a
TODO or something?

I thought that was the reason that these patches weren't picked up before?

That's what I thought, too.

quoted

I have no insight into this problem, so I can't comment on the technical
aspects, but I had made a note for myself 'locally' about it.

Using the RGA2 with the driver in its current form on devices with more than 4
GB system memory may lead to memory corruption as buffer addresses are
silently truncated to 32 bits.

That's because the driver is completely broken and is not using the DMA 
API anywhere near properly. The fact that it's been getting away with it 
so far can be mostly put down to good luck and nobody using 
CONFIG_DMA_API_DEBUG.

I'm not sure if that's actually a blocker for merging these patches.

If anything, hopefully getting more SoC support merged might provide 
more motivation for someone to fix the existing code :)

Robin.

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