From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753730AbcAOTKn (ORCPT ); Fri, 15 Jan 2016 14:10:43 -0500 Received: from mail.kmu-office.ch ([178.209.48.109]:49400 "EHLO mail.kmu-office.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751073AbcAOTKm (ORCPT ); Fri, 15 Jan 2016 14:10:42 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Date: Fri, 15 Jan 2016 11:08:31 -0800 From: Stefan Agner To: Mark Brown Cc: festevam@gmail.com, peterz@infradead.org, mingo@redhat.com, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: Lockdep warning when using REGCACHE_RBTREE In-Reply-To: <20160115162832.GY6588@sirena.org.uk> References: <20160115000144.GU6588@sirena.org.uk> <44832539ca2bcc0be6e08260083363fe@agner.ch> <20160115162832.GY6588@sirena.org.uk> Message-ID: <593bcd768227b953c0fc87cc0e5b175d@agner.ch> User-Agent: Roundcube Webmail/1.1.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016-01-15 08:28, Mark Brown wrote: > 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. Thanks for confirming that. I will switch to REGCACHE_FLAT then, I found a second driver with the very same issue, also a MMIO mapped device: drivers/pwm/pwm-fsl-ftm.c... -- Stefan