Hello everyone,I didn't use my sur40 for quite some time, but recently picked up work on it again. After a kernel update to 5.15, I noticed that the video component of the in-tree sur40 driver had apparently stopped working after 5.9 (this was actually noticed by @rwimmer a year ago, but I didn't properly follow up at the time).
This time, I did finally go through with a very tedious 14-step bisection of the issue and ended up at this commit:
https://github.com/torvalds/linux/commit/6eb0233ec2d0df288fe8515d5b0b2b15562e05bbThe issue manifests as a kernel oops in vb2_dma_sg_alloc, resulting in a failed usb_sg_init call (probably because dma_mask and dma_pfn_offset are now unset). How would I have to use the *_sg_* functions in my driver to fix this?
For reference, the code in question is: result = usb_sg_init(&sgr, sur40->usbdev, usb_rcvbulkpipe(sur40->usbdev, VIDEO_ENDPOINT), 0, sgt->sgl, sgt->nents, sur40->pix_fmt.sizeimage, 0);From looking at the other uses of usb_sg_init, would it be sufficient to change the very last parameter from 0 to either GFP_KERNEL or GFP_NOIO? If yes, which one is correct?
Best, Florian -- SENT FROM MY DEC VT50 TERMINAL
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