Hi,
-----Original Message----- From: linux-arm-kernel [mailto:linux-arm-kernel-bounces@lists.infradead.org] On Behalf Of Mark Brown Sent: Wednesday, October 29, 2014 7:37 PM To: Wang Huan-B18965 Cc: alsa-devel@alsa-project.org; tiwai@suse.de; linux-kernel@vger.kernel.org; lgirdwood@gmail.com; perex@perex.cz; linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] audio: sai: Add Power Management support
On Wed, Oct 29, 2014 at 11:21:36AM +0800, Alison Wang wrote:
This patch adds Power Management support for SAI. Activate regmap cache with REGCACHE_RBTREE, and use
Are you sure that REGCACHE_RBTREE is the best option here? For MMIO devices the cost tradeoff for the rbtree is usually higher than people like so flat caches are preferred. But if it works for you that's fine, this shouldn't be *that* performance critical.
Yes, the flat caches will have higher performance and can also fix the Register defaults and spinlock issue here.
One more thing, if the device is not performance critical, then shouldn't we Take care of the cache memory consumption to determine using flat or rbtree Type ?
Thanks,
BRs Xiubo
I'm also a bit surprised that this works without register defaults being provided since we need to make sure we allocate the rbtree nodes outside of the spinlock we use to lock MMIO access - was this tested with mainline?