On Fri, Aug 16, 2013 at 9:34 AM, Peter A. Bigot <p...@pabigot.com> wrote: > On 08/16/2013 08:38 AM, Tom Rini wrote: >> >> On Wed, Aug 14, 2013 at 09:53:16PM -0500, Peter A. Bigot wrote: >>> >>> On 07/09/2013 02:43 AM, Naumann Andreas wrote: >>>> >>>> In chapter 'Advisory 2.1 USB Host Clock Drift Causes USB Spec >>>> Non-compliance in Certain Configurations' of the TI Errata it is >>>> recommended >>>> to use certain div/mult values for the DPLL5 clock setup. >>>> So far u-boot used the old 34xx values, so I added the errata >>>> recommended values specificly for 36xx init only. >>>> Also, the FSEL registers exist no longer, so removed them from init. >>>> >>>> Tested this on a AM3703 board with 19.2MHz oscillator, which previously >>>> couldnt lock the dpll5 (kernel complained). As a consequence the EHCI USB >>>> port wasnt usable in U-Boot and kernel. With this patch, kernel panics >>>> disappear and USB working fine in u-boot and kernel. >>>> >>>> Signed-off-by: Andreas Naumann <anaum...@ultratronik.de> >>> >>> While this patch works with Linux that has been patched for this >>> erratum, it will cause problems with some unpatched versions of >>> Linux. >> >> Right. So Linux also needs to be patched for the erratum. > > > Yes. My point was that if you update u-boot alone, then try to use it to > boot an unpatched Linux that assumes CM_CLKSEL5_PLL has its power-on value, > USB will not work. > > I think it's dangerous to assume that the mixture of an unpatched Linux with > a patched u-boot will never occur, and the cause of the failure that results > is pretty subtle. So whatever gets merged would be safer if it restored the > default setting of CM_CLKSEL5_PLL prior to handing off control to Linux.
Agree, we should not apply this, till we also have an 'approved' patch for mainline linux posted. Right now we have a set of kernel hacks, but no agreed on method as the kernel maintainer did not have a board that suffered from the errata.. Regards, -- Robert Nelson http://www.rcn-ee.com/ _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot