[Mos] Fix Xe media engine reset on 32-bit media-driver

[matte-schwartz]

batch_addrs[0] (uint64_t) was cast through uintptr_t before assignment to exec.address (__u64). On 32-bit builds this truncates GPU VAs above 4GB, causing the kernel to reject or fault the dispatch and reset the media engine.

Pass batch_addrs[0] directly. For the array pointer branch, use the standard (uint64_t)(uintptr_t) idiom.

[matte-schwartz]

Sorry, I was under the impression given some older merged PRs in this repo (#1493) that 32-bit was somewhat supported, but I see now I was mistaken and that you've stated 32-bit builds are not supported: #1989 (comment).

This was actually for a media engine reset I ran into while looking into the feature requested in that issue, so it probably makes more sense to continue discussions there.

[fviolence]

I tested this patch on an Intel Arc Pro B70 system using the xe kernel driver, and it fixes the 32-bit H.264 VAAPI encode failure I was seeing.

Test environment (32-bit VAAPI stack):

OS: Arch Linux x86_64
GPU: Intel Arc Pro B70
Kernel driver: xe
lib32-libva 2.23.0
lib32-intel-gmmlib 22.10.0
lib32-intel-media-driver 26.1.5

Before applying this PR, 32-bit VAAPI initialized successfully, but actual encode failed. A minimal 32-bit FFmpeg H.264 VAAPI test failed with:

Failed to map output buffers: 24 (internal encoding error)
Output failed: -5
Error encoding a frame: Input/output error

Steam Remote Play showed the same effective failure through its 32-bit VAAPI path:

CGameStreamVideoStageVAAPI: Error encoding: Input/output error

After applying this PR, the same 32-bit FFmpeg H.264 VAAPI test succeeds. Steam Remote Play H.264 hardware encoding also works after applying the patch. The stream now uses HW encode, video is visible, and I no longer see the previous slow-encode / black-screen behavior in a short test.

So from my testing, this PR fixes a real 32-bit VAAPI H.264 encode failure on Battlemage / xe, and it also fixes Steam Remote Play H.264 hardware encoding on this system.

Any plans on merging the PR?

[matte-schwartz]

@fviolence fwiw, in case it doesn't get merged, using the SteamRT3 beta seems to work with just the 64-bit intel-media-driver needed.

[fviolence]

Yes, SteamRT3 indeed uses the 64-bit intel-media-driver. However, the feature itself is experimental, and the stream is barely usable because of occasional, but frequent image freezes.