From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: screen blank causing lockup in exynos-reference/exynos5-v3.18-rc2 Date: Mon, 24 Nov 2014 08:05:29 -0800 Message-ID: <7h4mtomvna.fsf@deeprootsystems.com> References: <8C.59.15273.8FB5F645@epcpsbgx1.samsung.com> <7h4mtsnys9.fsf@deeprootsystems.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from mail-pa0-f43.google.com ([209.85.220.43]:44252 "EHLO mail-pa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754037AbaKXQFc (ORCPT ); Mon, 24 Nov 2014 11:05:32 -0500 Received: by mail-pa0-f43.google.com with SMTP id kx10so9785943pab.30 for ; Mon, 24 Nov 2014 08:05:31 -0800 (PST) In-Reply-To: (Vivek Gautam's message of "Mon, 24 Nov 2014 14:57:08 +0530") Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Vivek Gautam Cc: Ajay Kumar , Vivek Gautam , PANKAJ KUMAR DUBEY , In-Ki Dae , "linux-samsung-soc@vger.kernel.org" , Javier Martinez Canillas , Amit Kucheria , "bhushan.r@samsung.com" Hi Vivek, Vivek Gautam writes: > On Sat, Nov 22, 2014 at 12:53 AM, Kevin Hilman wrote: >> Hi Ajay, >> >> AJAY KUMAR RAMAKRISHNA SHYMALAMMA writes: >> >>> I tried to reproduce the issue which you reported, >>> >>> but I am sorry I am not able to reproduce it. >>> >>> I tried with my patches for DRM on top of Linux-next. >> >> I don't see the issue on linux-next either. As I mentioned in the >> original post, I only see it on the v3.18 branch in the exynos-reference >> tree. > > While checking the issue along with Ajay on "exynos5-v3.18-rc2" branch > on exynos-reference > tree, we found out the culprit to be FIMD-SYSMMU. > The IOMMU on exynos systems is still WIP, and that's the reason it is > disabled in > exynos_defconfig too. > So we have a small workaround in this branch to stop using FIMD-SYSMMUs. > > Now, at the bootup time things are OK, since the FIMD-SMMU clocks > (CLK_SMMU_FIMD**) > are still available. But after bootup all unused clocks are disabled > (since we don't want to > use clk_ignore_unused in boot arguments), and the consequent blanking-unblanking > causes the system to hang. > > So we have pushed a patch on the same branch "exynos5-v3.18-rc2" which sets > CLK_IGNORE_UNUSED flag for these SMMU_FIMD** clocks. > > This fixes the issue of hang what we were seeing. > > There's another branch "exynos5-v3.18-rc5" available, and we have > pushed the same patch > on that branch too. > Please test on your side, and do let us know if things are working fine for you. I've tested the -rc5 branch, and I'm not seeing this issue anymore. Thanks, Kevin