Sebastian, Let's hope that the new standard cards support DMA. Standard itself is not sufficient to find out if these cards will or will not work - as I described or prior experience, manufacturers of one of the most popular CF card controllers made it incorrectly respond about the capabilities. So the only way to find out - try it - if it works - nice, if not - make a small investigation, maybe it is possible to fix in the driver.
About the UDMA - I have some emails from Axis with their hints, our investigating of the CF interfacing problems are described in the article http://www.linuxdevices.com/articles/AT5102023409.html Andrey On Sat, Feb 4, 2012 at 12:36 PM, Sebastian Pichelhofer < sebastian.pichelho...@gmail.com> wrote: > Thanks for the details, but CFAST is a completely new standard that > has little in common with CF cards and also requires totally different > adapters. > > Regarding the UDMA work around hints: Could you help me collect all > information together we currently have about it (info from axis > developer, etc.) so I can create a new wiki page describing the task > and then approach some people. > > Regards Sebastian > > On Sat, Feb 4, 2012 at 20:28, Andrey Filippov > <support-list@support.elphel.com> wrote: > > Sebastian, > > > > I just replied Carlos and wrote that the only problem with SATA devices > was > > with the old SSD made actually from the CF cards. Adapter is > transparent, > > so if the CF card does not work in the camera directly, it will not work > > with the adapter. For slow applications it is possible to disable DMA in > > the camera (needs adding the lying card to the blacklist and recompiling > the > > software). > > > > Devices support some of 3 modes: > > > > 1) PIO (slow and loads CPU a lot) > > 2) DMA - fast > > 3) UDMA - even faster > > Most CF cards support only 1 and 3 and respond as if they support 2 also > > ETRAX processor has a bug in implementation of the UDMA, so UDMA is > > disabled, that means that in the camera we only have 1 and 2. When the > > camera detects the disk, it loads the device capabilities (1,2,3), and > > selects the fastest it can support - 2. But here the lie of the CF card > > controller comes to the light - and the camera fails to communicate with > the > > disk. There is a black list of those untruthful cards in the driver, we > > already added some cards there - > > > 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 > > > > Axis engineers said that it is possible to mitigate that bug and gave > some > > hints how to do that, but we never worked on it ourselves and it is > probably > > not too easy - otherwise Axis people would do it themselves. But if > anybody > > with the driver development skills would volunteer - we would definitely > > love that and support such project. > > > > Andrey > > > > On Sat, Feb 4, 2012 at 11:53 AM, Sebastian Pichelhofer > > <sebastian.pichelho...@gmail.com> wrote: > >> > >> Do you think that http://en.wikipedia.org/wiki/CFast#CFast CFast Cards > >> could work with this adapter: > >> > >> > http://www.amazon.de/exec/obidos/ASIN/b003r4ifmg/geizhals1-21/ref=nosim?m=A3JWKAKR8XB7XF > >> connected to the Elphel camera over SATA. > >> > >> To my understanding the card itself acts like a drive and needs no > >> controller chip betweencard and camera that could lead to running into > >> the UDMA issues again. But the card itself might use UDMA... ;) > >> Any educated guesses? > >> > >> Regards Sebastian > >> > >> _______________________________________________ > >> Support-list mailing list > >> Support-list@support.elphel.com > >> > http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com > > > > > > _______________________________________________ > Support-list mailing list > Support-list@support.elphel.com > http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com >
_______________________________________________ Support-list mailing list Support-list@support.elphel.com http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com