At Sat, 28 Feb 2015 11:27:42 +0100, Lars-Peter Clausen wrote:
On 02/28/2015 11:01 AM, Takashi Iwai wrote:
At Sat, 28 Feb 2015 10:51:29 +0100, Lars-Peter Clausen wrote:
On 02/27/2015 10:28 PM, Takashi Iwai wrote:
For reducing the number of verbs performed during the initialization and the resume of the generic parser, this patch (re-)introduces the mechanism to cache everything in init and sync later.
However, it became a bit tricky in the end: we can't use regcache's cache_only flag straightforwardly here because we do want the actual hardware access for reads if needed, but forbids only the writes. So, instead, the regmap reg_write callback checks the own flag (reusing the existing codec->cached_write) and skips the actual access. This works by assumption of regmap dumping the whole registers via regcache_sync() at a later point.
Signed-off-by: Takashi Iwai tiwai@suse.de
sound/pci/hda/hda_generic.c | 4 ++++ sound/pci/hda/hda_regmap.c | 6 ++++++ 2 files changed, 10 insertions(+)
diff --git a/sound/pci/hda/hda_generic.c b/sound/pci/hda/hda_generic.c index 33de31c83d6e..bcaed93f8795 100644 --- a/sound/pci/hda/hda_generic.c +++ b/sound/pci/hda/hda_generic.c @@ -5411,6 +5411,8 @@ int snd_hda_gen_init(struct hda_codec *codec)
snd_hda_apply_verbs(codec);
- codec->cached_write = 1;
How about using regcache_cache_only(), this handles this internally in regmap and will also make sure that the cache gets marked as dirty so that a regcache_sync() will properly write out the dirty registers.
I tried this as a first option, too, but it doesn't work because we still want reading the value from hardware if not read beforehand. regcache_cache_only() prevents also from reading a h/w value. It's the point I mentioned this being tricky.
Hm, right, I skipped right past that. But I think it will still be better to implement this write-only caching in the regmap layer.
Yeah, that would make sense, I'm not against it :)
Takashi