Messages in this thread | | | From | Dong Aisheng <> | Date | Thu, 23 Jun 2022 00:42:51 +0800 | Subject | Re: [PATCH RFC 1/2] regmap: add option to disable debugfs |
| |
On Thu, Jun 23, 2022 at 12:27 AM Mark Brown <broonie@kernel.org> wrote:
> > > > - 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.
It was enabled by default according to the code: __regmap_init -> regcache_init
int regcache_init(struct regmap *map, const struct regmap_config *config) { int ret; int i; void *tmp_buf;
if (map->cache_type == REGCACHE_NONE) { if (config->reg_defaults || config->num_reg_defaults_raw) dev_warn(map->dev, "No cache used with register defaults set!\n");
map->cache_bypass = true; return 0; } }
Regards Aisheng
| |