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vgaarb: Don't default exclusively to first video device with mem+io

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Commit 20cde69402 ("x86, ia64: Move EFI_FB vga_default_device()
initialization to pci_vga_fixup()") moved boot video device detection from
efifb to x86 and ia64 pci/fixup.c.

For dual-GPU Apple computers above change represents a regression as code
in efifb did forcefully override vga_default_device while the merge did not
(vgaarb happens prior to PCI fixup).

To improve on initial device selection by vgaarb (it cannot know if PCI
device not behind bridges see/decode legacy VGA I/O or not), move the
screen_info based check from pci_video_fixup() to vgaarb's init function and
use it to refine/override decision taken while adding the individual PCI
VGA devices.  This way PCI fixup has no reason to adjust vga_default_device
anymore but can depend on its value for flagging shadowed VBIOS.

This has the nice benefit of removing duplicated code but does introduce a
#if defined() block in vgaarb.  Not all architectures have screen_info and
would cause compile to fail without it.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=84461
Reported-and-Tested-By: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Matthew Garrett <matthew.garrett@nebula.com>
CC: stable@vger.kernel.org # v3.5+
This commit is contained in:
Bruno Prémont
2014-08-24 23:09:53 +02:00
committed by Bjorn Helgaas
parent 52addcf9d6
commit 86fd887b7f
3 changed files with 39 additions and 47 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/gpu/vga/vgaarb.c
+37 -1
View File
@@ -41,6 +41,7 @@
#include <linux/poll.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/screen_info.h>
#include <linux/uaccess.h>
@@ -585,8 +586,11 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
*/
#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE
if (vga_default == NULL &&
((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK))
((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) {
pr_info("vgaarb: setting as boot device: PCI:%s\n",
pci_name(pdev));
vga_set_default_device(pdev);
}
#endif
vga_arbiter_check_bridge_sharing(vgadev);
@@ -1320,6 +1324,38 @@ static int __init vga_arb_device_init(void)
pr_info("vgaarb: loaded\n");
list_for_each_entry(vgadev, &vga_list, list) {
#if defined(CONFIG_X86) || defined(CONFIG_IA64)
/* Override I/O based detection done by vga_arbiter_add_pci_device()
* as it may take the wrong device (e.g. on Apple system under EFI).
*
* Select the device owning the boot framebuffer if there is one.
*/
resource_size_t start, end;
int i;
/* Does firmware framebuffer belong to us? */
for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
if (!(pci_resource_flags(vgadev->pdev, i) & IORESOURCE_MEM))
continue;
start = pci_resource_start(vgadev->pdev, i);
end = pci_resource_end(vgadev->pdev, i);
if (!start || !end)
continue;
if (screen_info.lfb_base < start ||
(screen_info.lfb_base + screen_info.lfb_size) >= end)
continue;
if (!vga_default_device())
pr_info("vgaarb: setting as boot device: PCI:%s\n",
pci_name(vgadev->pdev));
else if (vgadev->pdev != vga_default_device())
pr_info("vgaarb: overriding boot device: PCI:%s\n",
pci_name(vgadev->pdev));
vga_set_default_device(vgadev->pdev);
}
#endif
if (vgadev->bridge_has_one_vga)
pr_info("vgaarb: bridge control possible %s\n", pci_name(vgadev->pdev));
else