Bug#826629: Fwd: [PATCH] Fix loading of module radeonfb on PowerMac

[Mathieu Malaterre <malat@debian.org>]

Here is the full patch for reference.


---------- Forwarded message ----------
From: Mathieu Malaterre <malat@debian.org>
Date: Sat, Oct 8, 2016 at 2:09 PM
Subject: [PATCH] Fix loading of module radeonfb on PowerMac
To: linux-fbdev@vger.kernel.org
Cc: Lennart Sorensen <lsorense@csclub.uwaterloo.ca>, Tomi Valkeinen
<tomi.valkeinen@ti.com>, Jean-Christophe Plagniol-Villard
<plagnioj@jcrosoft.com>, Benjamin Herrenschmidt
<benh@kernel.crashing.org>, linuxppc-dev@lists.ozlabs.org, Mathieu
Malaterre <malat@debian.org>


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.

Signed-off-by: Mathieu Malaterre <malat@debian.org>
Link: https://bugs.debian.org/826629#57
Suggested-by: Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
---
 drivers/video/fbdev/aty/radeon_base.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbdev/aty/radeon_base.c
b/drivers/video/fbdev/aty/radeon_base.c
index 218339a..6f9bacd 100644
--- a/drivers/video/fbdev/aty/radeon_base.c
+++ b/drivers/video/fbdev/aty/radeon_base.c
@@ -2259,6 +2259,22 @@ static struct bin_attribute edid2_attr = {
        .read   = radeon_show_edid2,
 };

+static int radeon_kick_out_firmware_fb(struct pci_dev *pdev)
+{
+       struct apertures_struct *ap;
+
+       ap = alloc_apertures(1);
+       if (!ap)
+               return -ENOMEM;
+
+       ap->ranges[0].base = pci_resource_start(pdev, 0);
+       ap->ranges[0].size = pci_resource_len(pdev, 0);
+
+       remove_conflicting_framebuffers(ap, KBUILD_MODNAME, false);
+       kfree(ap);
+
+       return 0;
+}

 static int radeonfb_pci_register(struct pci_dev *pdev,
                                 const struct pci_device_id *ent)
@@ -2314,19 +2330,21 @@ static int radeonfb_pci_register(struct pci_dev *pdev,
        rinfo->fb_base_phys = pci_resource_start (pdev, 0);
        rinfo->mmio_base_phys = pci_resource_start (pdev, 2);

+       ret = radeon_kick_out_firmware_fb(pdev);
+       if (ret)
+               return ret;
+
        /* request the mem regions */
        ret = pci_request_region(pdev, 0, "radeonfb framebuffer");
        if (ret < 0) {
                printk( KERN_ERR "radeonfb (%s): cannot request region 0.\n",
                        pci_name(rinfo->pdev));
-               goto err_release_fb;
        }

        ret = pci_request_region(pdev, 2, "radeonfb mmio");
        if (ret < 0) {
                printk( KERN_ERR "radeonfb (%s): cannot request region 2.\n",
                        pci_name(rinfo->pdev));
-               goto err_release_pci0;
        }

        /* map the regions */
--
2.1.4