On Sat, Dec 5, 2015 at 8:03 AM, Ran Shalit <ranshalit@xxxxxxxxx> wrote: > 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=240, height=320 which result in > stable picture, but > the following timing gave me stable ppicture with LCD: > > Pixel clock=6500 > > Width=240 > Height=512 <<------------- instead of 320 !! > Hfp=1 > Hbp=100 > HSW=14 > Vfp=1 > Vbp=1 > VSW=10 > > 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 Hi, I wanted to add that framebuffer is configured as following: fbset -fb /dev/fb0 -xres 240 -yres 320 -vxres 240 -vyres 320 so, I don't know why dd if=/dev/zero of=/dev/fb0 results in image correct display starting with line 0 on the screen. I think that writing the image to framebuffer should have filled the complete buffer. Regards, Ran _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
