ASI 1600 MC: problem while capturing large images on Linux.

chripell

Hi, I am using the latest SDK under Linux and have problems while capturing full frames with 16 bits. I think there is a problem with issuing too many big bulk URB transfers in one go, which fails with ENOMEM (I'm adding a capture using LIBUSB_DEBUG to show the problem, look for errno=12). It looks like afterwards not all information is received and the ASI driver cancels the pending URBs (as you can see from the capture, look for libusb_cancel_transfer roughly 4s after the failed submission).

I have a pretty good USB3 laptop, so I'm ruling out performance problems. Also, the problem goes away if I capture 8 bit or (if I capture a smaller area in 16 bit and/or if I do 2x2 HW binning (I guess I reduce the amount of transferred data by a factor of 4)). I wrote a very short program to show the problem here: https://github.com/chripell/yaaca/blob/master/recorder.c

Any suggestions? Usually the USB wisdom says to have a "rolling" bulk USB submission (if you are fast enough that's not a problem, but this is an user space driver so it is a bit more difficult to meet strict timings).

Thanks!

PS: this said, ASI1600MC Cool is a wonderful camera, I'm attaching an M33 with just 206x20", no darks, flaky non-guided mout and no coma corrector for my newtonian.

PS2: never mind, cannot attach .txt files (huh!) you can see the capture here: http://www.evolware.org/dnload/asi.txt

chripell

Just to be more concrete: I think the problem is in the number of transfers. The dimension should not be a problem because modern USB controllers use scatter-gather and so they are OK with large ones. May I kindly ask to make the size parameter that you pass to libusb_alloc_transfer configurable? (instead of the default 1M) For example by using an environment variable such ASI_USB_TRANSFER_SIZE.

Thanks!

Sam@ZWO

Hi Chris

yes we used 1M buffer and async transfer

we will do more test to verify this issue

can you send one email to me?

I will forward to our software enginner

chripell

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chripell

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Sam@ZWO

actually, we added a short script to the asi.ruler

and you need to install it

sudo install asi.rules /lib/udev/rules.d

don't need to be so complicated ;)

USB bandwidth means the bandwidth the camera will use

100% means max fps

50% means half of the full bandwidth

this value is different in different computer

depends on USB host

chripell

D'oh missed /sys/module/usbcore/parameters/usbfs_memory_mb.

elmerfudd

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chripell

Just to confirm that version 1026 works perfectly. I only need to set USB bandwidth manually to 90 to have everything going smoothly (also full resolution x 16 bits x 1s).

The script is very simple:

/bin/echo 200 >/sys/module/usbcore/parameters/usbfs_memory_mb

Thanks!