Den 03.03.2021 14.32, skrev Thomas Zimmermann: > USB devices cannot perform DMA and hence have no dma_mask set in their > device structure. Therefore importing dmabuf into a USB-based driver > fails, which breaks joining and mirroring of display in X11. > > For USB devices, pick the associated USB controller as attachment device. > This allows the DRM import helpers to perform the DMA setup. If the DMA > controller does not support DMA transfers, we're out of luck and cannot > import. Our current USB-based DRM drivers don't use DMA, so the actual > DMA device is not important. > > Tested by joining/mirroring displays of udl and radeon under Gnome/X11. > > v8: > * release dmadev if device initialization fails (Noralf) > * fix commit description (Noralf) > v7: > * fix use-before-init bug in gm12u320 (Dan) > v6: > * implement workaround in DRM drivers and hold reference to > DMA device while USB device is in use > * remove dev_is_usb() (Greg) > * collapse USB helper into usb_intf_get_dma_device() (Alan) > * integrate Daniel's TODO statement (Daniel) > * fix typos (Greg) > v5: > * provide a helper for USB interfaces (Alan) > * add FIXME item to documentation and TODO list (Daniel) > v4: > * implement workaround with USB helper functions (Greg) > * use struct usb_device->bus->sysdev as DMA device (Takashi) > v3: > * drop gem_create_object > * use DMA mask of USB controller, if any (Daniel, Christian, Noralf) > v2: > * move fix to importer side (Christian, Daniel) > * update SHMEM and CMA helpers for new PRIME callbacks > > Signed-off-by: Thomas Zimmermann <[email protected]> > Fixes: 6eb0233ec2d0 ("usb: don't inherity DMA properties for USB devices") > Tested-by: Pavel Machek <[email protected]> > Reviewed-by: Greg Kroah-Hartman <[email protected]> > Acked-by: Christian König <[email protected]> > Acked-by: Daniel Vetter <[email protected]> > Cc: Christoph Hellwig <[email protected]> > Cc: Greg Kroah-Hartman <[email protected]> > Cc: <[email protected]> # v5.10+ > Signed-off-by: Thomas Zimmermann <[email protected]> > ---
Acked-by: Noralf Trønnes <[email protected]> _______________________________________________ dri-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/dri-devel
