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Commit 86fd887b authored by Bruno Prémont's avatar Bruno Prémont Committed by Bjorn Helgaas
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vgaarb: Don't default exclusively to first video device with mem+io 

Commit 20cde694 ("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: default avatarAndreas Noever <andreas.noever@gmail.com>
Signed-off-by: default avatarBruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
CC: Matthew Garrett <matthew.garrett@nebula.com>
CC: stable@vger.kernel.org # v3.5+
parent 52addcf9

arch/ia64/pci/fixup.c

+1 −23
Original line number Diff line number Diff line
@@ -38,27 +38,6 @@ static void pci_fixup_video(struct pci_dev *pdev) 
		return;

	/* Maybe, this machine supports legacy memory map. */



	if (!vga_default_device()) {

		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(pdev, i) & IORESOURCE_MEM))

				continue;



			start = pci_resource_start(pdev, i);

			end  = pci_resource_end(pdev, i);



			if (!start || !end)

				continue;



			if (screen_info.lfb_base >= start &&

			    (screen_info.lfb_base + screen_info.lfb_size) < end)

				vga_set_default_device(pdev);

		}

	}



	/* Is VGA routed to us? */

	bus = pdev->bus;

	while (bus) {
@@ -83,8 +62,7 @@ static void pci_fixup_video(struct pci_dev *pdev) 
		pci_read_config_word(pdev, PCI_COMMAND, &config);

		if (config & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {

			pdev->resource[PCI_ROM_RESOURCE].flags |= IORESOURCE_ROM_SHADOW;

			dev_printk(KERN_DEBUG, &pdev->dev, "Boot video device\n");

			vga_set_default_device(pdev);

			dev_printk(KERN_DEBUG, &pdev->dev, "Video device with shadowed ROM\n");

		}

	}

}

arch/x86/pci/fixup.c

+1 −23
Original line number Diff line number Diff line
@@ -326,27 +326,6 @@ static void pci_fixup_video(struct pci_dev *pdev) 
	struct pci_bus *bus;

	u16 config;



	if (!vga_default_device()) {

		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(pdev, i) & IORESOURCE_MEM))

				continue;



			start = pci_resource_start(pdev, i);

			end  = pci_resource_end(pdev, i);



			if (!start || !end)

				continue;



			if (screen_info.lfb_base >= start &&

			    (screen_info.lfb_base + screen_info.lfb_size) < end)

				vga_set_default_device(pdev);

		}

	}



	/* Is VGA routed to us? */

	bus = pdev->bus;

	while (bus) {
@@ -371,8 +350,7 @@ static void pci_fixup_video(struct pci_dev *pdev) 
		pci_read_config_word(pdev, PCI_COMMAND, &config);

		if (config & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {

			pdev->resource[PCI_ROM_RESOURCE].flags |= IORESOURCE_ROM_SHADOW;

			dev_printk(KERN_DEBUG, &pdev->dev, "Boot video device\n");

			vga_set_default_device(pdev);

			dev_printk(KERN_DEBUG, &pdev->dev, "Video device with shadowed ROM\n");

		}

	}

}

drivers/gpu/vga/vgaarb.c

+37 −1
Original line number Diff line number Diff line
@@ -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