From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin van der Gracht Date: Wed, 18 Jul 2012 09:29:58 +0000 Subject: Re: [BUGFIX] video/mxsfb: fix crash when unblanking the display Message-Id: <50068216.9020605@protonic.nl> List-Id: References: <1323174425-24038-1-git-send-email-LW@KARO-electronics.de> <20209.35406.958883.977664@ipc1.ka-ro> In-Reply-To: <20209.35406.958883.977664@ipc1.ka-ro> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: linux-arm-kernel@lists.infradead.org Hi Lothar, > Hi, > > Lothar Waßmann writes: >> 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. >> >> Signed-off-by: Lothar Waßmann >> --- >> 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 d837d63..03cb95a 100644 >> --- a/drivers/video/mxsfb.c >> +++ b/drivers/video/mxsfb.c >> @@ -366,7 +366,8 @@ 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(host->clk); >> >> -- >> 1.5.6.5 >> > Ping. Any comments on this? > > > Lothar Waßmann I've encountered this problem to, and i can confirm your patch fixed it. The VDCTRL4 register has no CLR feature. Regards, -- Robin van der Gracht Protonic Holland. tel.: +31 (0) 229 212928 fax.: +31 (0) 229 210930 Factorij 36 / 1689 AL Zwaag