From patchwork Thu Nov 22 12:49:14 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [BUGFIX] video: mxsfb: fix crash when unblanking the display Date: Thu, 22 Nov 2012 02:49:14 -0000 From: =?utf-8?q?Lothar_Wa=C3=9Fmann?= X-Patchwork-Id: 201042 Message-Id: <1353588555-13168-1-git-send-email-LW@KARO-electronics.de> To: linux-arm-kernel@lists.infradead.org Cc: linux-fbdev@vger.kernel.org, Shawn Guo , =?UTF-8?q?Lothar=20Wa=C3=9Fmann?= , Florian Tobias Schandinat The VDCTRL4 register does not provide the MXS SET/CLR/TOGGLE feature. The write in mxsfb_disable_controller() sets the data_cnt for the LCD DMA to 0 which obviously means the max. count for the LCD DMA and leads to overwriting arbitrary memory when the display is unblanked. Note: I already sent this patch in December 2011 but noone picked it up obviously. Signed-off-by: Lothar Waßmann Acked-by: Juergen Beisert Tested-by: Lauri Hintsala --- drivers/video/mxsfb.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/drivers/video/mxsfb.c b/drivers/video/mxsfb.c index 49619b4..f2a49ef 100644 --- a/drivers/video/mxsfb.c +++ b/drivers/video/mxsfb.c @@ -369,7 +369,8 @@ static void mxsfb_disable_controller(struct fb_info *fb_info) loop--; } - writel(VDCTRL4_SYNC_SIGNALS_ON, host->base + LCDC_VDCTRL4 + REG_CLR); + reg = readl(host->base + LCDC_VDCTRL4); + writel(reg & ~VDCTRL4_SYNC_SIGNALS_ON, host->base + LCDC_VDCTRL4); clk_disable_unprepare(host->clk);