Hello Shengjiu, On Wed, Jun 05, 2019 at 10:29:37AM +0000, S.j. Wang wrote: > > > ETDR is not volatile, if we mark it is volatile, is it correct? > > > > Well, you have a point -- it might not be ideally true, but it sounds like a > > correct fix to me according to this comments. > > > > We can wait for Mark's comments or just send a patch to the mail list for > > review. > > I test this patch, we don't need to reset the FIFO, and regcache_sync didn't > Write the ETDR even the EDTR is not volatile. This fault maybe caused by The fsl_esai driver uses FLAT type cache so regcache_sync() would go through regcache_default_sync() that would bypass cache sync at the regcache_reg_needs_sync() check when the cached register value matches its default value: in case of ETDR who has a default value 0x0, it'd just "continue" without doing that _regmap_write() when the cached value equals to 0x0. > Legacy, in the beginning we add this patch in internal branch, there maybe > Something cause this issue, but now can't reproduced. The "legacy" case might happen to have two mismatched ETDR values between the cached value and default 0x0. And I am worried it may appear once again someday. So I feel we still need to change ETDR to volatile type. And for your question "ETDR is not volatile, if we mark it is volatile, is it correct?", I double checked the definition of volatile_reg, and it says: * @volatile_reg: Optional callback returning true if the register * value can't be cached. If this field is NULL but So it seems correct to me then, as the "volatile" should be also transcribed as "non-cacheable". Thanks Nicolin _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
