On Thu, Sep 12, 2019 at 01:13:55PM +0900, Yoshihiro Shimoda wrote:
> The commit 38c38cb73223 ("mmc: queue: use bigger segments if DMA MAP
> layer can merge the segments") always enables the bugger segments

"buffer" :)

> if DMA MAP layer can merge the segments, but some controllers (SDHCI)
> have strictly limitation about the segments size, and then the commit
> breaks on the controllers.
> 
> To fix the issue, this patch adds a new flag MMC_CAP2_MERGE_CAPABLE
> into the struct mmc_host and the bigger segments usage is disabled
> as default.
> 
> Reported-by: Thierry Reding <treding@nvidia.com>
> Fixes: 38c38cb73223 ("mmc: queue: use bigger segments if DMA MAP layer can merge the segments")
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> Acked-by: Ulf Hansson <ulf.hansson@linaro.org>

For the record:

Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>