After learning the difference between GUID text and memory representation, I have hacked support into the kernel. And it doesn't work. The kernel tracing says this: mplayer says this: ---snip--- name: Video 4 Linux 2 input author: Martin Olschewski <olschewski@xxxxxxxxxxxxxxxx> comment: first try, more to come ;-) v4l2: your device driver does not support VIDIOC_G_STD ioctl, VIDIOC_G_PARM was used instead. Selected device: IR VIDEO: IR Camera Capabilities: video capture streaming supported norms: inputs: 0 = Camera 1; Current input: 0 Current format: RGB565 v4l2: ioctl set format failed: Input/output error v4l2: ioctl set mute failed: Invalid argument v4l2: 0 frames successfully processed, 0 frames dropped. ---snip--- mplayer says this: ---snip--- [17267.675757] usb 3-5.4.3: UVC non compliance - GET_DEF(PROBE) not supported. Enabling workaround. [17460.849025] uvcvideo 3-5.4.3:1.1: Failed to query (130) UVC probe control : -32 (exp. 26). (this last line appears when mplayer runs) ---snip--- v4l2-compliance's report on the format ioctls says this (the entire thing for both devices is on pastebin as it's big: https://pastebin.com/RAzpkigp) ---snip--- Format ioctls (Input 0): test VIDIOC_ENUM_FMT/FRAMESIZES/FRAMEINTERVALS: OK fail: v4l2-test-formats.cpp(1442): ret && node->has_frmintervals test VIDIOC_G/S_PARM: FAIL test VIDIOC_G_FBUF: OK (Not Supported) test VIDIOC_G_FMT: OK fail: v4l2-test-formats.cpp(767): Video Capture is valid, but no TRY_FMT was implemented test VIDIOC_TRY_FMT: FAIL fail: v4l2-test-formats.cpp(473): expected EINVAL, but got 5 whe n getting format for buftype 1 test VIDIOC_S_FMT: FAIL test VIDIOC_G_SLICED_VBI_CAP: OK (Not Supported) test Cropping: OK (Not Supported) test Composing: OK (Not Supported) fail: v4l2-test-formats.cpp(1853): doioctl(node, VIDIOC_S_FMT, & fmt) fail: v4l2-test-formats.cpp(2001): testBasicScaling(node, fmt) test Scaling: FAIL ---snip--- I'm feeling like this is a very ill camera. However, capturing does work on Windows. I see there is support for UVC device quirks (https://elixir.bootlin.com/linux/v6.10.10/source/drivers/media/usb/uvc/uvcvideo.h#L63). Any suggestions of anything which might work? I tried a few things randomly and nothing seemed to make a difference. On Thu, 12 Sept 2024 at 12:52, Ricardo Ribalda <ribalda@xxxxxxxxxxxx> wrote: > > Hi David > > > On Wed, 11 Sept 2024 at 21:58, David Given <dg@xxxxxxxxxxx> wrote: > > > > Hello, > > > > I've just received a review sample thermal camera which doesn't work > > with Linux uvcvideo. It's reporting itself as providing a D3DFMT GUID: > > > > ---snip--- > > VideoStreaming Interface Descriptor: > > bLength 27 > > bDescriptorType 36 > > bDescriptorSubtype 4 (FORMAT_UNCOMPRESSED) > > bFormatIndex 1 > > bNumFrameDescriptors 1 > > guidFormat > > {e436eb7b-524f-11ce-9f53-0020af0ba770} > > bBitsPerPixel 16 > > bDefaultFrameIndex 1 > > bAspectRatioX 0 > > bAspectRatioY 0 > > bmInterlaceFlags 0x00 > > Interlaced stream or variable: No > > Fields per frame: 2 fields > > Field 1 first: No > > Field pattern: Field 1 only > > bCopyProtect 0 > > ---snip--- > > > > This corresponds to D3DFMT_R5G6B5 or MEDIASUBTYPE_RGB565, based on the > > reference here: https://gix.github.io/media-types/#ID0EC2AI However, > > the UVC driver is expecting RGB565 to be using the 4cc RGBP GUID > > 52474250-0000-1000-8000-00aa00389b71. This is very nearly the same as > > the alternative GUID described on the document above, > > 00000017-0000-0010-8000-00AA00389B71, which uses an index rather than > > a 4cc. > > > > I haven't been able to find any references as to what GUIDs are > > supported for guidFormat. > > The uvc spec only defines GUIDs for YUY2, NV12, M420 and I420. > > It would have been nice that the vendor had used the same GUID as > TomTom (Check 507910799160e85eac5e7729e0d2f1ba26f6a8cf) > but apparently it is not required to be like this. > > > Why dont you try adding a new mapping to include/linux/usb/uvc.h and > drivers/media/common/uvc.c ? Similar to what Marek did here: > 015d44c2b700ba9639dd29672ba362796cc0be54 > > I believe that if a camera does not use TomToms GUID and the new GUI, > everything would work... > > Regards > > > > > (a) Is the camera wrong? > > (b) Is the kernel wrong? > > (c) Am I looking at the wrong document? > > > > The easy fix is to patch the uvcvideo driver to support the e436... > > GUID, but that doesn't seem a great idea. Any suggestions? > > > > > -- > Ricardo Ribalda
