Re: Rootfs in eMMC: Kernel panic ...Attempted to kill init!

From: Sudeep K N
Date: Tue Jun 23 2009 - 01:58:33 EST

> Could you or Sudeep clarify whether the driver uses DMA or PIO?
I have option to use both. I tried you patch(rather hack) for PIO mode i.e
(flush_dcache_page called in the VFS layer). This solves the crash in polling
mode. I need to work for proper way of flushing in the MMC driver.
I am yet to try with DMA as I am not much familiar with the DMA driver and
need some time.

> In my case (ext2 over pata_platform), there is no flush_dcache_page()
> call after the page was written with data from the CompactFlash (neither
> the driver nor the VFS layer do this and we used hardware tracing to
> double-check). When the page is mapped into user space,
> update_mmu_cache() is called but the page hasn't been marked as dirty
> and no D-cache flushing occurs. Calling flush_dcache_page() in
> mpage_end_io_read() works around this issue.

Looks like the crash I am getting is similar to one you are explaining with
your experience with CF cards.

Thanks to both Catalin and Russell for making such a informative discussion on
ARM SMP and related cache know hows.

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