Hi Bartlomiej, On Wed, Jan 3, 2018 at 4:23 PM, Lennart Sorensen <lsorense@xxxxxxxxxxxxxxxxxxx> wrote: > On Wed, Jan 03, 2018 at 03:47:35PM +0100, Bartlomiej Zolnierkiewicz wrote: >> On Thursday, December 21, 2017 11:07:56 PM Mathieu Malaterre wrote: >> > When the linux kernel is build with (typical kernel ship with Debian >> > installer): >> > >> > CONFIG_FB_OF=y >> > CONFIG_VT_HW_CONSOLE_BINDING=y >> > CONFIG_FB_RADEON=m >> > >> > The offb driver takes precedence over module radeonfb. It is then >> > impossible to load the module, error reported is: >> > >> > [ 96.551486] radeonfb 0000:00:10.0: enabling device (0006 -> 0007) >> > [ 96.551526] radeonfb 0000:00:10.0: BAR 0: can't reserve [mem 0x98000000-0x9fffffff pref] >> > [ 96.551531] radeonfb (0000:00:10.0): cannot request region 0. >> > [ 96.551545] radeonfb: probe of 0000:00:10.0 failed with error -16 >> > >> > This patch reproduce the behavior of the module radeon, so as to make it >> > possible to load radeonfb when offb is first loaded. >> > >> > It should be noticed that `offb_destroy` is never called which explain the >> > need to skip error detection on the radeon side. >> >> This still needs to be explained more, from my last mail: >> >> "The last put_fb_info() on fb_info should call ->fb_destroy >> (offb_destroy in our case) and remove_conflicting_framebuffers() >> is calling put_fb_info() so there is some extra reference on >> fb_info somewhere preventing it from going away. >> >> Please look into fixing this." > > My impression of that problem is that the offb driver is in use because > it is running the console, and until the radeonfb driver is loaded and > ready to take over, you can't stop using the offb driver, but you can't > currently load the radeonfb because offb is holding resources it wants. > > Maybe I have misunderstood what the code is doing, but that seems to be > the problem. > > On an x86 PC you could drop one fb and go to text mode then start another > fb driver. PPC doesn't have that option since there is no text mode. For reference my patch was inspired by commit: https://github.com/torvalds/linux/commit/a56f7428d7534f162fbb089c5c79012bf38a7c29 While doing the search, I discover my patch is incorrect, I need to integrate change from: https://github.com/torvalds/linux/commit/44adece57e2604cec8527a499b48e4d584ab53b8#diff-767fb253c0135686111755f394d64199 So I'll submit a v4 anyway. Thanks all, -- 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
