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.
Try CONFIG_MMC_BOUNCE_BUFFER or what it was called ... see inclued/configs/m28evk.h , I use it there.
Best regards, Marek Vasut