On Mon, Oct 07, 2013 at 11:57:35AM +0200, David Jander wrote: > On Mon, 7 Oct 2013 08:41:11 +0200 > Sascha Hauer <s.ha...@pengutronix.de> wrote: > > > On Mon, Oct 07, 2013 at 08:32:03AM +0200, David Jander wrote: > > > > > > Dear Sascha, > > > > > > On Sun, 6 Oct 2013 12:39:50 +0200 > > > Sascha Hauer <s.ha...@pengutronix.de> wrote: > > > > > > > > It doesn't interfere with the kernel. The kernel currently ignores this > > > > aliases. There are patches floating to let the kernel honor this > > > > aliases, but then they should simply have the same effect as they have > > > > in barebox. > > > > > > That doesn't _feel_ right. Changing standard device names in Linux via > > > aliases in the DT might be a fancy idea, but it'd have a different > > > reason/use-case than in the case of barebox. IMHO using the same DT for > > > both seems to be the Right Thing (tm) to do, but then the semantics must > > > be the same also. If I need aliases in the DT only to be able to tell > > > devices apart from each other in barebox, while in Linux the effect would > > > only be a rather inconvenient renaming of devices with no other added > > > value, I think we need a different way to differentiate devices in > > > barebox. Why not just use a simple driver-provided prefix (mci, mmc, usb, > > > sata, etc...) for now? > > > > That's not enough. We also need a fixed numbering. Otherwise a > > nonremovable eMMC and a removable SD card change their device names > > depending on the detect order. > > True. Can host->dev.id be used? Should be fixed AFAICS...
host->dev.id depends on the probe order. > > > Using aliases to provide a numbering is done in the Kernel aswell at > > least for gpios, uarts and i2c busses, so expanding this scheme to > > mmc/sd slots doesn't feel too wrong to me. > > Yes, but we are doing it in barebox now only because there is no other way to > tell devices apart from each other. While the MMC device being called > "mmcblk0" or whatever in Linux is perfectly fine (no need for alias), Linux has exactly the same problem. There are enough systems on which the eMMC changes its name depending on a SD card being plugged in or not. > in > barebox the device is now named "disk0", and there is no way of knowing what > "disk0" actually is. Using DT-aliases for that purpose seems wrong to me. > Why was this changed anyway? Introduction of some common "disk" layer (like > scsi-disk on Linux)? Or just for the sake of confusing it with other > "disk"-like devices? It has always been diskx on barebox, this behaviour hasn't changed. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox
