Allow dcp interchange to scanout interchange compressed

[oliverbestmann]

Works together with this mesa MR:
https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/39755

[Conan-Kudo]

The UAPI change needs to be separately contributed to Linux directly, not this fork.

See this documentation: https://docs.kernel.org/process/submitting-patches.html

[jannau]

For experimenting we should move this into the driver with

#ifndef DRM_FORMAT_MOD_APPLE_INTERCHANGE_COMPRESSED
#define DRM_FORMAT_MOD_APPLE_INTERCHANGE_COMPRESSED fourcc_mod_code(APPLE, 3)
#endif

I'm not sure if we want one or more APPLE_INTERCHANGE_COMPRESSED modifiers to handle YCbCr formats which use 32x32 tiles for Y

[chadmed]

Is this enough of a difference to warrant a new format modifier? If the tile size only changes for the luma channel of Y'CbCr textures, can we not just handle that by checking is_yuv for the framebuffer format info struct? E.g.

tile_w = fb->format->is_yuv ? 32 : 16

[waltmck]

Thank you for the exciting work!

I tested this with nixos-apple-silicon 6.10 using your flake, on an M2 Macbook Air. Hyprland fails to launch with the following repeated log message:

kernel: apple-dcp 231c00000.dcp: swap failed! status 4
kernel: dcp: plane 0 modifiers: c00000000000003
kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: UPPipe.cpp:3920: IOMFB verify_uc_surface: Planesize insufficient for data plane size 17039360, data size 17301504
kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: UPPipeDCP_H13P.cpp:4554: bool IOMFB::UPPipeDCP_H13P::verify_surfaces(IOMFB::SwapRequest *): Error with the interchange surface
kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: FramebufferDCP.cpp:2175: AppleCLCD: verify_swap failed for swap id: 4285

[oliverbestmann]

@waltmck

I tested this with nixos-apple-silicon 6.10 using your flake, on an M2 Macbook Air.

Thank you. Is that with the notch enabled or disabled? And what's your selected display resolution?

It was not working with hyprland on my machine too. I've fixed the issue now. Please try again with the latest update to the flake.

[waltmck]

@waltmck

I tested this with nixos-apple-silicon 6.10 using your flake, on an M2 Macbook Air.

Thank you. Is that with the notch enabled or disabled? And what's your selected display resolution?

It was not working with hyprland on my machine too. I've fixed the issue now. Please try again with the latest update to the flake.

With your latest flake I can run Hyprland (and I've been using it to work for the last few hours without issues). Is there an easy way to check with certainty that compressed scanout is actually being used?

[oliverbestmann]

You can use drm_info to see that modifier c00000000000003 is used for the plane.

[waltmck]

You can use drm_info to see that modifier c00000000000003 is used for the plane.

yep, I do see that so it seems to be working.

[jannau]

the code misses a check to ensure the computed surface size for interchange framebuffers fits into the framebuffer's reported buffer size

[oliverbestmann]

the code misses a check to ensure the computed surface size for interchange framebuffers fits into the framebuffer's reported buffer size

Whats the expected behavior in that case? assert and kernel panic, or some logging and quietly ignoring the plane?

[jannau]

the code misses a check to ensure the computed surface size for interchange framebuffers fits into the framebuffer's reported buffer size

Whats the expected behavior in that case? assert and kernel panic, or some logging and quietly ignoring the plane?

check needs to happen in atomic_check where it can fail, possible that there there are drm_format helpers for that using driver specific formats (I would have to check myself)

[chadmed]

Tested as mostly-working on G14G, G14S and G13S, however overlays are broken on kwin. May be size/alignment related, as fractional scaling factors and certain cursor images (notably the Breeze I-beam) cause framebuffer creation to fail. This is most obvious with the cursor, but may occur with other oddly-sized overlay framebuffers.

[oliverbestmann]

Tested as mostly-working on G14G, G14S and G13S, however overlays are broken on kwin. May be size/alignment related, as fractional scaling factors and certain cursor images (notably the Breeze I-beam) cause framebuffer creation to fail. This is most obvious with the cursor, but may occur with other oddly-sized overlay framebuffers.

Thank you. I had no problems running this with kde. I'll try to reproduce the issues as soon as I can.

[jannau]

the comment from the drm_fourcc.h description would be more more appropriate:

/*
 *  ... The metadata section rounds the image dimensions to
 * powers-of-two and contains 8 bytes for each 16x16 compression subtile.
 * Subtiles are interleaved (Morton order).
 */

It's the most up to date description.