From mboxrd@z Thu Jan 1 00:00:00 1970 From: Javier Martinez Canillas Subject: Re: [PATCH 1/1] ARM: exynos_defconfig: Disable IOMMU support Date: Tue, 17 Feb 2015 13:56:25 +0100 Message-ID: <54E33A79.3060904@collabora.co.uk> References: <1424173109-30347-1-git-send-email-javier.martinez@collabora.co.uk> <1424175623.14482.4.camel@AMDC1943> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from bhuna.collabora.co.uk ([93.93.135.160]:60895 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756292AbbBQM4b (ORCPT ); Tue, 17 Feb 2015 07:56:31 -0500 In-Reply-To: <1424175623.14482.4.camel@AMDC1943> Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Krzysztof Kozlowski Cc: Kukjin Kim , Olof Johansson , Marek Szyprowski , Andreas Faerber , linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org Hello Krzysztof, On 02/17/2015 01:20 PM, Krzysztof Kozlowski wrote: > On wto, 2015-02-17 at 12:38 +0100, Javier Martinez Canillas wrote: >> Enabling Exynos DRM IOMMU support for Exynos is currently broken and >> causes a BUG on exynos-iommu driver. This was not an issue since the >> options was disabled in exynos_defconfig but after commit 8dcc14f82f06 >> ("drm/exynos: IOMMU support should not be selectable by user"), it is >> selected if EXYNOS_IOMMU is enabled which is in exynos_defconfig. >> >> So a kernel built using exynos_defconfig after the mentioned commit >> fails to boot [0]. Disable IOMMU support in Exynos defconfig until >> things get sorted out. > > On which board you got this error? > Sorry, I should had mention it in the commit message. I get that error with at least Exynos5800 Peach Pi, Exynos5420 Peach Pit and Exynos5250 Snow Chromebooks with today's next (next-20150217). The problem is that the Exynos IOMMU driver does not set a struct exynos_iommu_owner in dev.archdata.iommu but __exynos_sysmmu_enable() has a BUG_ON(!has_sysmmu(dev)). Marek's series [1] solves this issue by filling sysmmu devices from DT but causes boot failures on the Exynos Chromebooks because the display is left enabled by the bootloader [2]. So I think that this option should be disabled until is known to not cause issues on any platform. > Best regards, > Krzysztof > [1]: http://lists.infradead.org/pipermail/linux-arm-kernel/2015-January/319244.html [2]: http://lists.infradead.org/pipermail/linux-arm-kernel/2015-January/319293.html