From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joonyoung Shim Subject: Re: [PATCH v3 00/19] Exynos SYSMMU (IOMMU) integration with DT and DMA-mapping subsystem Date: Tue, 20 Jan 2015 20:12:59 +0900 Message-ID: <54BE383B.5030505@samsung.com> References: <1416395748-10731-1-git-send-email-m.szyprowski@samsung.com> <1417514366.21830.22.camel@collabora.co.uk> <54818768.3080303@samsung.com> <54AC93E0.8010705@samsung.com> <54ACFD69.1020500@collabora.co.uk> <54AD0293.70909@samsung.com> <54AEB384.2040005@collabora.co.uk> <54B36C5A.6050109@samsung.com> <54B3F1B7.7090307@collabora.co.uk> <54B4ABFB.5000501@samsung.com> <54B5B5F6.3030607@collabora.co.uk> <54B5B721.4070309@collabora.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <54B5B721.4070309@collabora.co.uk> Sender: linux-samsung-soc-owner@vger.kernel.org To: Javier Martinez Canillas , Javier Martinez Canillas , Marek Szyprowski Cc: linaro-mm-sig@lists.linaro.org, "linux-samsung-soc@vger.kernel.org" , Shaik Ameer Basha , Arnd Bergmann , Rob Herring , Gustavo Padovan , Joerg Roedel , Will Deacon , iommu@lists.linux-foundation.org, Tomasz Figa , Inki Dae , Sjoerd Simons , Kukjin Kim , Laurent Pinchart , Olof Johansson , Kyungmin Park , Thierry Reding , Cho KyongHo , David Wodhouse , "linux-arm-kernel@lists.infradead.org" List-Id: iommu@lists.linux-foundation.org Hi, On 01/14/2015 09:24 AM, Javier Martinez Canillas wrote: > On 01/14/2015 01:19 AM, Javier Martinez Canillas wrote: >> >> I dug further on this issue and found that the cause is that the exynos_mixer >> driver needs some clocks (CLK_HDMI and CLK_SCLK_HDMI) grabbed by exynos_hdmi >> to be kept enabled after hdmi_poweroff (drivers/gpu/drm/exynos/exynos_hdmi.c). >> >> Otherwise, any access to mixer device registers leads to an imprecise external >> abort error. The following change [0] to the Exynos DRM HDMI driver makes the >> issue to not happen and I can successfully execute: >> >> # echo 1 > /sys/devices/platform/exynos-drm/graphics/fb0/blank >> # echo 0 > /sys/devices/platform/exynos-drm/graphics/fb0/blank >> Did you execute this operation repeatedly? Still i get error when i execute this more than twice with your change [0]. Thanks. >> Only not disabling the hdmi clock [1]: is enough but doing so makes sometimes the >> DISP1 power domain disabling fails. It doesn't seem to have side effect though >> since I also see the signal in the HDMI display to go standby and then on again. >> >> # echo 0 > /sys/devices/platform/exynos-drm/graphics/fb0/blank >> # echo 1 > /sys/devices/platform/exynos-drm/graphics/fb0/blank >> [ 63.089080] Power domain disp1-power-domain disable failed >> # echo 0 > /sys/devices/platform/exynos-drm/graphics/fb0/blank >> # >> >> That error message when both clocks are not disabled on hdmi_poweroff() though. >> > > This should be: "That error message is not shown when both clocks are disabled". > > Best regards, > Javier >