Qball's Weblog

Good linux support!

Tags General 

Let me try to work away the backlog of things I wanted to blog about.

The first one is a story of good linux support:


For a course I was preparing we needed a way to stream back the tft (vga/dvi) output generated by an FPGA board. In previous years we had  a setup with a screen and webcam in front of the screen.

This year I tried to do it a bit nicer.  Looking around, the cheapest solution, that has linux drivers, was an epiphan VGA2USB

It is expensive, but it seems to do what we want. It can take a vga output and converts it to a v4l stream. But most important it seems to have drivers for the kernel used in Ubuntu 11.10. This was down to the last version (3.0.0-14). Also it looked like it was updated regular.

The problem

After installing the driver, it worked fine for normal laptop output. Also video playback was fine. However when connecting it to the FPGA board, it failed when updating the whole screen to fast, or when we reprogrammed the board (and there is no input for 10 seconds).

The ‘fail’ resulted in a kernel panic and worst case even crash of the USB bus..

Getting help

So I got information about the crash to file a bug report. But no detailed information on the website where the hell to send this too. So I decided to mail it to info@epiphan.com.

Response time

6 hours after my mail, I had a reply. This contained a debug build of the driver and some specific questions.  I ran the debug driver, got more debug information  (like 6 megabytes of it) and sended this back.

The solution

less then 2 days later I got another e-mail with a new driver that fixes the problem. So within one workweek (3 days!!!) I had a fixed driver.  This is the best commercial support I ever had. (Lets not talk about f.e.  NVidia that doesn’t even want to admit a bug in there video cards that causes them to randomly start giving back wrong values when using cuda)

After Though

Would I buy this device again..  Not sure..  The support is _great_, the device does what it sais.  But quality is lower then expected, it interlaces like crazy (Because it only buffers a single line), for 300 euro I expect better. The version that ‘fixes’ this costs 700 euros (with tax).