Re: Lockdep warning when using REGCACHE_RBTREE

From: Mark Brown
Date: Fri Jan 15 2016 - 11:28:52 EST


On Thu, Jan 14, 2016 at 05:14:47PM -0800, Stefan Agner wrote:

> On a slightly other topic, I question whether REGCACHE_RBTREE is the
> right cache type for the DCU DRM driver. The driver has uses a regmap
> area of 1144 32-bit registers, the most space is used by the layer
> configuration registers which are 0x40 apart and 0x0-0x20 for each layer
> are actually used (hence somewhat above 50%).

> Would FLAT be the better cache type?

Yes, and if it's a MMIO device the performance of a flat cache is more
in line with the device performance.

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