From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ran Shalit Date: Sat, 05 Dec 2015 06:03:56 +0000 Subject: wipe framebuffer with dd command Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kernelnewbies@lists.kernelnewbies.org Hello, I would like to ask what is the effect of wiping frame buffer (dd if=/dev/zero of=/dev/fb0) ? I have some issue with framebuffer timing on LCD 240x320. I could not find a timing with width$0, height20 which result in stable picture, but the following timing gave me stable ppicture with LCD: Pixel clocke00 Width$0 HeightQ2 <<------------- instead of 320 !! Hfp=1 Hbp0 HSW Vfp=1 Vbp=1 VSW The only strange thing is that I had to use height 512 instead of 320. When I try to render image it is stable but it starts in different line every time. And here comes the important part: After doing: dd if=/dev/zero of=/dev/fb0 It resolved the issue , and a new image starts from line 0. I don't understand why. Does anyone have any idea ? Do you think I still have a timing problem with LCD ? Regards, Ran