Re: [RFC, PATCH] gspca pac7302: propagate footer to userspace
Hi Németh, On 01/24/2010 06:20 PM, Németh Márton wrote: Hi, I'm dealing with Labtec Webcam 2200 and I found that the pac7302 driver does not forward the image footer information to userspace. This footer contains some information which might be interesting to the userspace. What exactly this footer means is not clear as of this writing, but it is easier to analyze the data in userspace than in kernel space. I modified the sd_pkt_scan() in order the footer is transfered to the userspace together with the image. This, however, breaks the image decoding in libv4lconvert. This is can be easily solved by passing the image buffer to v4lconvert_convert() truncated by 0x4f bytes. What do you think the right way would be to transfer image footer to userspace? I agree that in retrospect sending the footer to userspace is a good idea, but see below. Is it necessary to add a new V4L2_PIX_FMT_* format in order not to brake userspace programs? Yes that is the only sensible way I see to do this, which IMHO is a too high price to pay for just getting this info out of the kernel while we are not doing anything with it. Now if we actually find a good use for this in userspace, then I think we can do this, but until then I think you need to do this with a local patch. Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[RFC, PATCH] gspca pac7302: propagate footer to userspace
Hi, I'm dealing with Labtec Webcam 2200 and I found that the pac7302 driver does not forward the image footer information to userspace. This footer contains some information which might be interesting to the userspace. What exactly this footer means is not clear as of this writing, but it is easier to analyze the data in userspace than in kernel space. I modified the sd_pkt_scan() in order the footer is transfered to the userspace together with the image. This, however, breaks the image decoding in libv4lconvert. This is can be easily solved by passing the image buffer to v4lconvert_convert() truncated by 0x4f bytes. What do you think the right way would be to transfer image footer to userspace? Is it necessary to add a new V4L2_PIX_FMT_* format in order not to brake userspace programs? PAC7302 footer structure I could figure out so far is: Offset | Length |Description ---++-- 0x0 | 1| Seen values: 0x10, 0x11, 0x12, 0x13, 0x15, 0x16 || Some kind of sequence number or timestamp? ---++-- 0x1 | 1| Seen values: 0x50 ---++-- 0x2 | 1| Seen values: 0x00 ---++-- 0x3 | 1| Seen values: 0x00 ---++-- 0x4 | 1| Seen values: 0x00 ---++-- 0x5 | 1| Seen values: 0x00 ---++-- 0x6 | 25 | Picutre lumination related bytes. || The gain setting has influcence on the values || In test modes: || test mode 1 (white): filled with 0xFE || test mode 2 (black): filled with 0x00 || test mode 3 (red): filled with 0x4C || test mode 4 (green): filled with 0x96 || test mode 5 (blue):filled with 0x1C || test mode 6 (cyan):filled with 0xB3 || test mode 7 (magenta): filled with 0x69 || test mode 8 (yellow): filled with 0xE1 || test mode 9 (color bars): || 9B 6A 7B B1 52 71 68 6B 76 62 9F 9F 9F 9F 9F 8D 61 70 A1 4B 99 6A 7A AF 52 || test mode 10 (high resolution color pattern): || A8 AC A5 A6 A6 A3 A3 A1 A2 A4 A2 9F 9F A0 A5 A5 9F 9F 9C A5 A9 A5 A2 A2 A7 || test mode 11 (black to white gradient from top to bottom): || 4B 6E 8A A4 BF 48 6A 85 9E B8 47 68 83 9C B5 47 69 84 9D B7 49 6C 88 A1 BC || test mode 12 (white to black gradient from left to right): || 5A 57 57 57 59 80 7D 7D 7D 80 A0 9D 9C 9C A0 BF BB BA BB BE DC D7 D6 D7 DB || test mode 13 (white to black gradient repeats from left to right): || A8 A5 A4 A5 A7 A4 A0 9F A0 A4 A4 A0 A2 A0 A3 A5 A2 A2 A1 A5 A5 A3 A2 A2 A5 || test mode 14 (dark gray): filled with 0x00 || test mode 15 (dark gray2): filled with 0x00 ---++-- 0x1f |1 | Seen: 0x00 ---++-- 0x20 |2 | Picture content related? ---++-- 0x22 |1 | Seen: 0x00 ---++-- 0x23 |2 | Compressed picture size related? ---++-- 0x25 |1 | Seen: 0x00 ---++-- 0x26 |1 | Seen: 0x00 ---++-- 0x27 |1 | Seen: 0x00 ---++-- 0x28 |4 | Picture content related? ---++-- 0x2c |4 | Picture content related? ---++-- 0x30 |4 | Picture content related? ---++-- 0x34 |4 | Picture content related? ---++-- 0x38 |1 | Seen: fixed 0x01 ---++-- 0x39 |1 | Seen: fixed 0xAE ---++-- 0x3a |1 | Seen: fixed 0x01 ---++-- 0x3b |1 | Seen: fixed 0x04 ---++-- 0x3c |1 | Seen: fixed 0x16 ---++-- 0x3d |1 | Seen: fixed 0x14 ---++--
