RESOLVED FIXED294995
[WPE] Memory-mapped GPU buffers fail under DRM platform 
https://bugs.webkit.org/show_bug.cgi?id=294995
Summary [WPE] Memory-mapped GPU buffers fail under DRM platform
Nikolas Zimmermann
Reported 2025-06-25 14:40:45 PDT
When using the DRM platform (new API) memory-mapped GPU buffers on i.MX platforms with split GPU/IPU failed. The DRM platform implementation selects the first KMS-capable DRM node (e.g. /dev/dri/card1, with no corresponding render node -> a display controller) as DRM device to allocate buffers for display purposes (which is correct). However we asked that DRM node for its render node, which is non-existant, and thus /dev/dri/card1 was also passed on as 'drmRenderNode' to DRMDeviceManager, which in turn is used througout WebCore for buffer allocation purposes, where we want to allocate buffers that are _not_ displayed, but used within rendering -- in that case we should be using the GPU (here: /dev/dri/card0, /dev/dri/renderD128). The main device (GPU) and the target device (IPU, display controller) might differ. The Wayland platform handles this correctly by listening to `main_device` and `tranche_target_device' linux-dmabuf-v1 events. The GPU is correctly used as 'main device', whereas the display-controller is used as 'target device' -- fix DRM to behave the same.
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Nikolas Zimmermann
Comment 1 2025-06-25 14:49:26 PDT
Pull request: https://github.com/WebKit/WebKit/pull/47208
EWS
Comment 2 2025-07-08 15:02:36 PDT
Committed 297131@main (e3ab4a2e6678): <https://commits.webkit.org/297131@main> Reviewed commits have been landed. Closing PR #47208 and removing active labels.
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