> the sfb->fb->screen_base is not save the value get by iounmap() when > the chip id is 0x720. I suggest to improve this change description. How did you determine relevant differences for the mentioned chip model? > so iounmap() for address sfb->fb->screen_base is not right. Will another imperative wording become helpful here? … > +++ b/drivers/video/fbdev/sm712fb.c > @@ -1429,6 +1429,8 @@ static int smtc_map_smem(struct smtcfb_info *sfb, > static void smtc_unmap_smem(struct smtcfb_info *sfb) > { > if (sfb && sfb->fb->screen_base) { > + if (sfb->chip_id == 0x720) > + sfb->fb->screen_base -= 0x00200000; > iounmap(sfb->fb->screen_base); How do you think about to use descriptive identifiers for the shown constants? Would you like to clarify any related software analysis approaches? Regards, Markus