Hello, Am 19.12.2010 12:28, schrieb Albert ARIBAUD: > Le 19/12/2010 11:22, Alexander Holler a écrit : >> Hello, >> >> On 19.12.2010 08:51, Dirk Behme wrote: >>> On 18.12.2010 23:27, Alexander Holler wrote: >>>> gcc 4.5.1 seems to ignore (at least some) volatile definitions, >>>> avoid that as done in the kernel. >>>> >> >>> Acked-by: Dirk Behme<dirk.be...@googlemail.com> >> >> Thanks for the ack, but I have to say, that those barriers are having >> side effects here. Reading NAND now fails on my BeagleBoard. Regardless >> if I use gcc 4.3.5 or gcc 4.5.1, after applying that patch the wrong ID >> of the NAND is read. In nand_get_flash_type() >> (drivers/mtd/nand/nand_base.c) without that patch I will get the following: >> >> *maf_id: 44, dev_id: 186 >> >> with the patch the following is read: >> >> *maf_id: 128, dev_id: 85 >> >> Which just is wrong. >> >> I haven't looked further up to now, maybe thats just a side effect of >> some wrong clock settings because of different timings through those >> barrieres or whatever. > > IIUC, the patch is adding barriers to every HW register write and read, > which makes the compiler stop reordering these, and keep them ordered as > in the source code. Are you sure that the order as laid out in the > source is the right one? Maybe you were just luck so far that the > reordering masked a bug.
I don't know much about all the stuff the omap3-drivers are doing. E.g. I've already wondered why it's necessary to measure a clock frequency in the code which got (wrongly) optimized without that patch. I would think such isn't necessary because I would assume the drivers are actually there to set the clock settings, and not to measure them. ;) Regards, Alexander _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
