Hell Labs

Last week I came across a no-brand, very cheap-looking USB webcam with id 0ac8:0323 and recognized by Linux as a “Z-Star Microelectronics Corp. Luxya WC-1200 USB 2.0 Webcam”, which seems to be misleading in this case.

From the USB ID it is supposed to contain a Vimicro VC0323 controller, and it was recognized as so by the GSPCA driver. This camera, however, seems to have a number of quirks that cause the driver to decode the image incorrectly: the image is fed as YUV instead of Jpeg (like the VC0321), image start offset is different from what the driver expects for VC0323 or VC0321, and finally the sensor appears to be mounted upside-down inside the camera. Read on for fix details and GSPCA patches.

(more…)

The following patch allows the Syntek 174f:5212 camera found in some HP laptops (including the Compaq Presario C700 series) to be used in Linux with the linux-uvc driver. The image quality is fairly good, with decent colors, white balance and frame rate in luvcview. The patch is a bit intrusive since it requires quirk testing at the start of the isochronous payload frame decoding to completely bypass synchronization, but it seems to work very well. This patch is against revision 158 of the linux-uvc subversion repository.

• Add quirk for Syntek 174f:5212 UVC camera Wrong! Use Herton’s Laurent’s patch below.
• Add quirk for Syntek 174f:5212 UVC camera (fixed version)
• Laurent Pinchart’s final patch

Syntek camera framegrabs: 1, 2.

Update: Posted Herton Krzesinski’s fixed version. Posted Laurent Pinchart’s final version.