fix(mesa): Zink on PowerVR shows colour again instead of grayscale (#2287)

Mesa 26.0.8, which the Ubuntu runtime builds, carries the backport of
"zink: create views for samplers lazily", which dropped the depth/stencil
aspect check in init_sampler_view(). On drivers with
needs_zs_shader_swizzle (Imagination) every colour view with a constant-1
alpha, such as RGBX/BGRX textures, then got the red-only depth swizzle
view, so Steam's interface and games showed red as R=G=B.

Carry Icenowy Zheng's upstream fix d55418dae7 (Mesa MR 41923), which
restores the aspect check. It applies on top of patch 0004.

README.md

@@ -79,6 +79,7 @@ DroidDeck is [GPL-3.0](LICENSE). Steam and Proton belong to Valve Corporation. V
 - droiddeck-ntsync follows the [Linux](https://github.com/torvalds/linux) ntsync semantics in `Documentation/userspace-api/ntsync.rst` (GPL-2.0).
 - The proot fast path orders bindings like [PRoot](https://github.com/proot-me/proot)'s `path/binding.c` (GPL-2.0-or-later).
 - DiRT 3 and DiRT Showdown keep their telemetry socket the way RoccoC's DiRTTelemetryErrorFix (MIT) does, based on the fix by Carsten Gottschling.
+- Zink on PowerVR keeps colour textures in colour with Icenowy Zheng's upstream [Mesa](https://gitlab.freedesktop.org/mesa/mesa) fix d55418dae7 (MIT), carried as a runtime patch.
 - Games use [Mesa](https://gitlab.freedesktop.org/mesa/mesa) Turnip's per render pass memory choice. The Steam client keeps `TU_DEBUG=sysmem`.
 - Black Ops III and Dark Souls Remastered start without [umu-protonfixes](https://github.com/Open-Wine-Components/umu-protonfixes) (BSD-2-Clause), whose `311210.py` and `570940.py` fail under ARM64 Proton.
 - [ReSkate](https://github.com/Dingo-Shenanigans/ReSkate) (GPL-3.0) by Dingo Shenanigans uses the launch option from its README and D3D12 feature level 12_1.

tools/ubuntu/README.md

@@ -9,7 +9,8 @@ Steam on the desktop). The app installs it into `files/linuxfs` and runs it unde
   `/dev/kgsl-3d0`, and KWin with `patches/kwin` (nested desktop scale, an explicit render node,
   scroll source/discrete forwarding). Both get a `+droiddeck` version. `patches/mesa` adds KGSL
   UBWC 5/6 (backported from upstream Mesa) and the KGSL device numbers for WSI (from
-  [Droid-Deck/Drivers](https://github.com/Droid-Deck/Drivers)).
+  [Droid-Deck/Drivers](https://github.com/Droid-Deck/Drivers)). It also carries Icenowy Zheng's upstream
+  Zink fix that keeps the Imagination depth/stencil swizzle off colour views (Mesa d55418dae7).
 - The runtime's built-in Vulkan driver is DroidDeck's DD-Turnip Linux build (`DD_TURNIP_URL` and
   `DD_TURNIP_SHA256` in `base.env`): Ubuntu's Turnip is diverted to `libvulkan_freedreno.so.distrib`
   because it lacks the Adreno 8xx fixes. Zink, EGL and llvmpipe stay Ubuntu's.

tools/ubuntu/patches/mesa/0005-zink-check-zs-aspect-before-creating-zs-view.patch

@@ -0,0 +1,41 @@
+From d55418dae753c8daacf66ab81a7481094808576a Mon Sep 17 00:00:00 2001
+From: Icenowy Zheng <zhengxingda@iscas.ac.cn>
+Date: Sun, 31 May 2026 21:56:32 +0800
+Subject: [PATCH] zink: check Z/S aspect before creating Z/S image view
+
+When moving the code of creating image views to the init_sampler_view()
+function, the check for Z/S aspect bits was forgotten to be added
+(because it was a big if gating a lot of code originally).
+
+When the driver doesn't have needs_zs_shader_swizzle set, this is not
+problematic, because the condition for creating Z/S view is to have only
+Z aspect; however the needs_zs_shader_swizzle case now fails because Z/S
+views are now created for color images.
+
+Fix the issue by re-adding the Z/S aspect check before checking
+needs_zs_shader_swizzle flag.
+
+Fixes: cafa22142bf1 ("zink: create views for samplers lazily")
+Signed-off-by: Icenowy Zheng <zhengxingda@iscas.ac.cn>
+Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/41923>
+---
+ src/gallium/drivers/zink/zink_context.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/src/gallium/drivers/zink/zink_context.c b/src/gallium/drivers/zink/zink_context.c
+index e264e57b2703..41bc1b6932a7 100644
+--- a/src/gallium/drivers/zink/zink_context.c
++++ b/src/gallium/drivers/zink/zink_context.c
+@@ -1173,7 +1173,8 @@ init_sampler_view(struct zink_context *ctx, struct zink_sampler_view *sv)
+ 
+    bool red_depth_sampler_view = false;
+    if (sv->ivci.subresourceRange.aspectMask == VK_IMAGE_ASPECT_DEPTH_BIT ||
+-       screen->driver_compiler_workarounds.needs_zs_shader_swizzle) {
++       ((sv->ivci.subresourceRange.aspectMask & (VK_IMAGE_ASPECT_DEPTH_BIT | VK_IMAGE_ASPECT_STENCIL_BIT)) &&
++        screen->driver_compiler_workarounds.needs_zs_shader_swizzle)) {
+       VkComponentSwizzle *swizzle = (VkComponentSwizzle*)&sv->ivci.components;
+       for (unsigned i = 0; i < 4; i++) {
+          if (swizzle[i] == VK_COMPONENT_SWIZZLE_ONE ||
+-- 
+GitLab
+