Hello, Andrey, thanks for the quick response! I'm also online (here it is 3:40am) =)
My Kingston cards are not listed in the blacklist. Let's get them to work and see how far they go. Here are the results of the tests, I'm ssh-ed into the cam: [root@Elphel353 /mnt/0]944# time dd if=/dev/circbuf of=/dev/null 38656+0 records in 38656+0 records out real 0m 0.42s user 0m 0.03s sys 0m 0.39s [root@Elphel353 /mnt/0]944# time dd if=/dev/circbuf of=/dev/hdb1 38656+0 records in 38656+0 records out real 0m 6.75s user 0m 0.19s sys 0m 2.46s [root@Elphel353 /mnt/0]944# If I understood correctly, my card takes 6.75 seconds to write the 19MB and 19 MB / 6.75 = 2.8MB/s should be the maximum data rate my cards can handle, is that it? Meanwhile, I've tested normal HD JP4, at 720p and observed that compression 100% is a killer, but at about 90%, the recording proceeded without cutting the video, even tough the gui refresh rate suffered. ps.: I considered buying the Sundisk Extreme III, but I saw they were not being sold at B&H at the moment. =/ If there is any other you would recommend... Thanks! flavio 2012/4/26, Andrey Filippov <[email protected]>: > Hello Flavio, > > Most likely the problem is related to the CF - as I wrote in that old > article, most CF cards in IDE mode lie about support of the DMA mode. They > do support UDMA so most people never notice that small lie. But Axis CPU > used in the camera has a bug of it's own - and this bug is related to the > UDMA. If the card would hostly report that it does not support DMA camera > driver would just go to PIO mode (ABSOLUTELY NOT SUITABLE for the video > recording - both slow and using to much of the camera CPU resources), but > it does not, so camera may hang up and never come out of the boot scripts. > So what we did was to add some known "bad" cards to the driver black list: > > > http://elphel.cvs.sourceforge.net/viewvc/elphel/elphel353-8.0/os/linux-2.6-tag--devboard-R2_10-4/drivers/ide/ide-dma.c?view=markup(lines > 130..136). > > At some point we black-listed all no-name cards (we did not find any among > them that did support DMA) You may use hdparm -I (from > http://192.168.0.9/phpshell.php, telnet or serial console that you should > have cable for) and the only way to re-enable (if you card matches the > black-listed one) the card is to modify that file and recompile the camera > firmware. The only type of CF cards we use ourselves is "Sandisk Extreme > III". > > When the card is blacklisted, camera bots correctly and is able to mount > (and use) the card - it can be used to save images or very slow video > (still useful for timelapse), but not the normal video. > > You may test the speed of the CF card (that test will destroy data on it!) > with the following command (again - phpshell, telnet, serial console): > > time dd if=/dev/circbuf of=/dev/hda #(or hdb - depending how is the card > inserted/configured) > > /dev/circbuf is the circular buffer ~19MB in size that is very fast to read > for the camera, so the speed will be related to the CF itself > > You may try it on /dev/null first: > > [root@Goniometer /dev]16713# time dd if=/dev/circbuf of=/dev/null > 38656+0 records in > 38656+0 records out > real 0m 0.43s > user 0m 0.11s > sys 0m 0.32s > > With phpshell you may just open the following link (provided you have the > default IP) - just replace all spaces in the command line with "+" signs > http://192.168.0.9/phpshell.php?command=time+dd+if=/dev/circbuf+of=/dev/null > > Then divide 19MB by the time measured. > > Andrey > _______________________________________________ Support-list mailing list [email protected] http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com
