Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753887AbcCYQ1f (ORCPT ); Fri, 25 Mar 2016 12:27:35 -0400 Received: from mail.kmu-office.ch ([178.209.48.109]:43014 "EHLO mail.kmu-office.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753501AbcCYQ1e (ORCPT ); Fri, 25 Mar 2016 12:27:34 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Date: Fri, 25 Mar 2016 09:24:28 -0700 From: Stefan Agner To: Alexander Stein Cc: Alison Wang , David Airlie , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] drm: fsl-dcu: Use flat cache In-Reply-To: <1458826413-3916-1-git-send-email-alexander.stein@systec-electronic.com> References: <1458826413-3916-1-git-send-email-alexander.stein@systec-electronic.com> Message-ID: <43567cc2f2f6b3b7d1a06a094f6ff90a@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 Content-Length: 1551 Lines: 47 Hi Alexander, On 2016-03-24 06:33, Alexander Stein wrote: > Using REGCACHE_RBTREE for MMIO regmap is not valid as spinlock's will be > used during cache allocation. > > This fixes the following bug: > BUG: sleeping function called from invalid context at mm/slab.h:388 > in_atomic(): 1, irqs_disabled(): 128, pid: 192, name: udevd > [...] > > Signed-off-by: Alexander Stein > --- > Please refer also to the discussion at > https://lists.freedesktop.org/archives/dri-devel/2016-January/098696.html > > drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c > b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c > index e8d9337..ea65140 100644 > --- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c > +++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c > @@ -40,7 +40,7 @@ static const struct regmap_config fsl_dcu_regmap_config = { > .reg_bits = 32, > .reg_stride = 4, > .val_bits = 32, > - .cache_type = REGCACHE_RBTREE, > + .cache_type = REGCACHE_FLAT, To use flat regcache you also need to set the max_register. I already have such a patch, see: https://lists.freedesktop.org/archives/dri-devel/2016-January/099121.html However, the current suspend/resume implementation (which uses the regcache) is anyway flawed. I currently prepare a patchset to remove the regmap cache entirely and use Thierry's new generic suspend/resume functions. -- Stefan > > .volatile_reg = fsl_dcu_drm_is_volatile_reg, > };