On Tue, Feb 15, 2011 at 5:48 PM, Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> wrote: > On Tue, Feb 15, 2011 at 03:35:44PM +0800, Eric Miao wrote: >> > @@ -720,12 +726,10 @@ static int overlayfb_open(struct fb_info *info, int user) >> > Â Â Â Âif (user == 0) >> > Â Â Â Â Â Â Â Âreturn -ENODEV; >> > >> > - Â Â Â /* allow only one user at a time */ >> > - Â Â Â if (atomic_inc_and_test(&ofb->usage)) >> > - Â Â Â Â Â Â Â return -EBUSY; >> > + Â Â Â if (ofb->usage++ == 0) >> > + Â Â Â Â Â Â Â /* unblank the base framebuffer */ >> > + Â Â Â Â Â Â Â fb_blank(&ofb->fbi->fb, FB_BLANK_UNBLANK); >> >> The change above allows multiple user at a time? Then I guess >> some other places need to be changed accordingly to avoid the >> racing conditions. > > You can't prevent multiple users. ÂThink threaded applications which > share the same set of fds. > > Any driver which tries to do so by restricting the number of open()s is > simply buggy. > OK, let's go ahead fix the racing conditions later. -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
