From mboxrd@z Thu Jan 1 00:00:00 1970 From: Albert ARIBAUD Date: Thu, 3 Oct 2013 10:55:58 +0200 Subject: [U-Boot] [PATCH 2/2] RFC: exynos: Disable the display controller when starting Linux In-Reply-To: <1380791060-2578-2-git-send-email-ajaykumar.rs@samsung.com> References: <1380791060-2578-1-git-send-email-ajaykumar.rs@samsung.com> <1380791060-2578-2-git-send-email-ajaykumar.rs@samsung.com> Message-ID: <20131003105558.41900743@lilith> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Ajay, On Thu, 03 Oct 2013 14:34:20 +0530, Ajay Kumar wrote: > If the exynos display controller is still active when Linux starts, > then it will result in a kernel panic while FIMD sysmmu driver is > getting probed. > Calling exynos_fimd_lcd_disable() before jumping into kernel > disables the display controller by switching off the windows, > hence resolving the kernel panic which arises from sysmmu driver. > > Create an Exynos specific definition for the weak function > arch_cleanup_before_linux(), and then place the call to > exynos_fimd_lcd_disable() inside the overrided definition of > arch_cleanup_before_linux(). > > Signed-off-by: Ajay Kumar > Signed-off-by: Simon Glass > --- Why should the fix to this situation be making U-Boot disable the display controller rather than making Linux able to cope with an already active display controller? Besides, fixing Linux would allow seamless booting displays, without an ugly off-on glitch. Amicalement, -- Albert.