On Sat, Feb 4, 2012 at 21:24, Andrey Filippov <support-list@support.elphel.com> wrote: > 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.
Will do, I should be able to get both card and adapter for less than 100€ and will report back with results. > > 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 If you could dig them out that would be great. Regards Sebastian > > 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