On Thu, Sep 26, 2024 at 07:31:49AM +0200, Ahmad Fatoum wrote: > On 25.09.24 16:34, Sascha Hauer wrote: > > the splash command has an option for setting a background colour. This > > doesn't always fill the whole screen as expected. > > > > struct fb_info has a line_length field that specifies the length in > > bytes of a single line. That length may be bigger than the actually > > visible area as specified by xres. In this case filling the area as > > calculated by xres*yres fills the invisible pixels between xres and > > line_length, but it doesn't fill the whole visible area. Fix this by > > iterating over the lines, filling the visible area of each line. > > I have trouble understanding this. What is line_length if not > bytes per pixel multiplied by xres?
Some hardware might have alignment restrictions on the address where the new line starts. In that case line_length is longer than xres*bpp. Also the picture in the framebuffer might be wider than the visible area. In my case I allocate a framebuffer for the biggest resolution the monitor supports. When changing the resolution to a smaller one I can keep the framebuffer and still show something useful by keeping line_length and just adjusting xres. Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
