Problem when trying to capture image from USB web camera

Hi

What is the pixel resolution (width and height) of this capture ? Have you tried with any other resolution.

What is the PSP version used?

Regards

Ravi B

The resolution of that image is 640 x 480. I've tried with a couple of other web cameras, and higher resolutions does not work (error depend on camera and resolution...) while lower resolutions (say 320 x 480 ) does work. There doesn't seem to be an exact limit on which the image capturing stop working. However, when configuring the camera to use MJPEG format when grabbing images it all works just fine, but for this project we want YUYV formatted data. Since there seem to be a correlation between amount of data transmitted and This has led me to believe that the error somehow is USB related. A collegue of mine said he have heard of a similar problem, which was caused by USB buffers not being activated. Could there be some truth to this, and if so how do I activate the buffers.

Regarding PSP version I'm not sure which version I'm using, how do find this?

Emil

Can you try applying this patch from arago

http://arago-project.org/git/projects/?p=linux-omap3.git;a=blobdiff;f=drivers/usb/musb/musb_host.c;h=554359a7d91074f8282d67586a67c1ddde7976c5;hp=3b0548c32fda42ad8cf3893a9a1327d804c6a825;hb=b05173a0fcd7f0093a01b1f373cd8c6501659fad;hpb=2d4dad1795e501fba0a40a200180f01ceb27a986

Regards

Ravi B

I tried the patch, but it didn't help. Is there some way I could debug this, or try to get some logs to examine?

Oh, and btw, I'm running PSP 04.00.00.12

Regards
Emil

Emil,

From the description of the issue it appears that bandwidth could be a issue.  Pl. check for the fifo sizes for the EP's that are being used for the transfer.  In MJPEG mode the video is received as a compressed stream and hence would work fine.  In the raw YUV mode you would need more throughput/bandwidth.  Ensure that the EP's are correctly configured for the same.

regards

swami

Hi!

Sorry for the long delay. This sound like a fully plausible cause. Where can check the fifo sizes? Is this a SysFS-configuration?

Regards
Emil

Using the last version (PSP 4.00.01.13-patch1)  with the arago patch fixed the problem. It is now possible to grab 3Mpixel images.

However, it seems a bit unsafe to fix the problem by removing spinlocks. Could this pose a problem somewhere else?

Thanks for all the help :)'

Best regards
Emil Ohlsson

Emil

There is no issue in this case. Because the patch you are referred is the extension orignal patch "musb: Add workqueue for URB giveback" with commit-id cc42fb3688e2c68eb2b4fb1a23752e7a26fa03fd. This patch is to reduce the delay in programming the usb transfer to avoid any timing gap for isochronous transfers, where saperate worker thread used to give back all completed URBs. This patch removed the spin_locks used in worker thread, there is no necessity of using the spin_locks for the completed the URBs.

Regards

Ravi B