Messages in this thread | | | Date | Wed, 22 Jun 2022 17:27:09 +0100 | From | Mark Brown <> | Subject | Re: [PATCH RFC 1/2] regmap: add option to disable debugfs |
| |
On Thu, Jun 23, 2022 at 12:05:46AM +0800, Dong Aisheng wrote: > On Wed, Jun 22, 2022 at 8:36 PM Mark Brown <broonie@kernel.org> wrote:
> > On Wed, Jun 22, 2022 at 06:12:49PM +0800, Dong Aisheng wrote: > > > > > NOTE: i didn't fix _regmap_write() as i.MX controls regmap write well in driver > > > with power enabled first, so don't have issues in reality.
> > I can't tell what you think the problem is with _regmap_write()?
> Because from what I see, _regmap_write() seems still can write to HW > register even with cache_only mode set theoretically.
Ah, I see - we don't enforce cache_only if bypass is enabled somehow, but we will complain if you try to enable both at the same time so I'm not sure that's an issue?
> > > - WARN_ON(map->cache_bypass && enable); > > > +// WARN_ON(map->cache_bypass && enable);
> > What is the purpose of this change? Why would the combination of cache > > only and bypass modes work be a good idea, and how should things behave > > in that case?
> Because without this change, there will be a kernel dump caused by > WARN_ON when drivers call regcache_cache_only(map, true) after power > is off. There's no cache used in the imx blkctl driver. So map->cache_bypass > is default to true.
cache_bypass is only going to be true if something enabled bypass, why would a device that doesn't use a cache enable bypass? It does get turned on transiently by things like patching but those only make sense if the device can be accessed so caceh_only shouldn't be on then. [unhandled content-type:application/pgp-signature] | |