On Fri, Oct 20, 2017 at 12:12:41PM +0900, Yoshihiro Shimoda wrote:
> Since the commit de3ee99b097d ("mmc: Delete bounce buffer handling")
> deletes the bounce buffer handling, a request data size will be referred
> to max_{req,seg}_size instead of MMC_QUEUE_BOUNCESZ (64k bytes).
>
> In other hand, renesas_sdhi_internal_dmac.c will set very big value of
> max_{req,seg}_size because the max_blk_count is set to 0xffffffff.
> And then, "swiotlb buffer is full" happens because swiotlb can handle
> a memory size up to 256k bytes only (IO_TLB_SEGSIZE = 128 and
> IO_TLB_SHIFT = 11).
>
> So, as a workaround, this patch avoids the issue by setting
> the max_{req,seg}_size up to 256k bytes if swiotlb is running.
>
> Reported-by: Dirk Behme <dirk.behme@xxxxxxxxxxxx>
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
For the issues we are seeing with v4.14, I think this fix is good. We
plan to fully fix this issue at a more generic level, then this addition
can go again. But we are not there yet, and likely need some additional
API, so:
Acked-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
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