On Fri, Sep 14, 2012 at 08:53:32AM -0700, Simon Glass wrote: > Hi, > > On Wed, Sep 12, 2012 at 4:42 PM, Marek Vasut <ma...@denx.de> wrote: > > Dear Stephen Warren, > > > >> On 09/12/2012 04:38 PM, Marek Vasut wrote: > >> > Dear Stephen Warren, > >> > > >> >> On 09/12/2012 10:19 AM, Tom Warren wrote: > >> >>> Folks, > >> >>> > >> >>> Stephen Warren has posted an internal bug regarding the cache > >> >>> alignment 'warnings' seen on Tegra20 boards when accessing MMC. Here's > >> >>> the gist: > >> >>> > >> >>> Executing "mmc dev 0" still yields cache warnings: > >> >>> > >> >>> Tegra20 (Harmony) # mmc dev 0 > >> >>> ERROR: v7_dcache_inval_range- stop address is not aligned- 0x3fb69908 > >> >>> mmc0 is current device > >> >> > >> >> ... > >> >> > >> >>> There have been patches in the past (IIRC) that have tried to ensure > >> >>> all callers (FS, MMC driver, USB driver, etc.) force their buffers to > >> >>> the appropriate alignment, but I don't know that we can ever correct > >> >>> every instance, now or in the future. > >> >>> > >> >>> Can we start a discussion about what we can do about this warning? > >> >>> Adding an appropriate #ifdef (CONFIG_SYS_NO_CACHE_ALIGNMENT_WARNINGS, > >> >>> etc.) where Stephen put his #if 0's would be one approach, or changing > >> >>> the printf() to a debug(), perhaps. As far as I can tell, these > >> >>> alignment 'errors' don't seem to produce bad data in the transfer. > >> >> > >> >> I don't think simply turning off the warning is the correct approach; I > >> >> believe they represent real problems that can in fact cause data > >> >> corruption. I don't believe we have any choice other than to fully solve > >> >> the root-cause. > > Yes I agree, and I think it is pretty close - certainly much better > than it used to be. The good thing about them being annoying is that > they will likely get fixed :-)
I think I traced this to the copying of CSD a while back. The problem is that the transferred buffer is 8 bytes, so there's no way to make it aligned properly. Unfortunately the entailing discussion did not yield a solution at the time. Thierry
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