Messages in this thread | | | Date | Mon, 14 Mar 2022 12:32:45 +0200 | Subject | Re: [PATCH] mmc: block: enable cache-flushing when mmc cache is on | From | Adrian Hunter <> |
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On 14/03/2022 09:26, Avri Altman wrote: > Hi, >> The mmc core enable cache on default. But it only enables cache-flushing >> when host supports cmd23 and eMMC supports reliable write. >> For hosts which do not support cmd23 or eMMCs which do not support >> reliable write, the cache can not be flushed by `sync` command. >> This may leads to cache data lost. >> This patch enables cache-flushing as long as cache is enabled, no matter host >> supports cmd23 and/or eMMC supports reliable write or not. > I looked in the spec and indeed couldn't find why enabling cache is dependent of cmd23/reliable write. > Nor I was able to find the original commit log.
Reliable write was added first, so it might have been an oversight:
commit 881d1c25f765938a95def5afe39486ce39f9fc96 Author: Seungwon Jeon <tgih.jun@samsung.com> Date: Fri Oct 14 14:03:21 2011 +0900
mmc: core: Add cache control for eMMC4.5 device
This patch adds cache feature of eMMC4.5 Spec. If device supports cache capability, host can utilize some specific operations.
Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com> Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com> Signed-off-by: Chris Ball <cjb@laptop.org>
> > Please allow few days to ask internally. > > Thanks, > Avri
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