[PATCH 2/3] Split VGA default device handler out of VGA arbiter
Daniel Axtens
dja at axtens.net
Fri Aug 4 20:20:32 AEST 2017
A system without PCI legacy resources (e.g. ARM64, powerpc) may
find that no default/boot VGA device has been marked, because the
VGA arbiter checks for legacy resource decoding before marking a
card as default.
Split the small bit of code that does default VGA handling out from
the arbiter. Add a Kconfig option to allow the kernel to be built
with just the default handling, or the arbiter and default handling.
(You can try with the arbiter and no default handling - I can't see
why that wouldn't work but it seems a bit odd to try.)
Add handling for devices that should be marked as default but aren't
handled by the vga arbiter by adding a late initcall and a class
enable hook. If there is no default from vgaarb then the first card
that is enabled, has a driver bound, and can decode memory or I/O
will be marked as default.
Signed-off-by: Daniel Axtens <dja at axtens.net>
---
I haven't tested this particularly deeply just yet as I wanted to
see if anyone had Strong Feelings before I put too much time into
testing. I have verified that it works on ppc with qemu TCG, both
with and without the following patch.
I know this adds another config option and that's a bit sad, but
we can't include it unconditionally as it depends on PCI.
Suggestions welcome.
---
arch/ia64/pci/fixup.c | 2 +-
arch/powerpc/kernel/pci-common.c | 2 +-
arch/x86/pci/fixup.c | 2 +-
arch/x86/video/fbdev.c | 2 +-
drivers/gpu/vga/Kconfig | 12 +++
drivers/gpu/vga/Makefile | 1 +
drivers/gpu/vga/vga_default.c | 159 +++++++++++++++++++++++++++++++++++++++
drivers/gpu/vga/vga_switcheroo.c | 2 +-
drivers/gpu/vga/vgaarb.c | 41 +---------
drivers/pci/pci-sysfs.c | 2 +-
include/linux/vga_default.h | 44 +++++++++++
include/linux/vgaarb.h | 14 ----
12 files changed, 225 insertions(+), 58 deletions(-)
create mode 100644 drivers/gpu/vga/vga_default.c
create mode 100644 include/linux/vga_default.h
diff --git a/arch/ia64/pci/fixup.c b/arch/ia64/pci/fixup.c
index 41caa99add51..b35d1cf4501a 100644
--- a/arch/ia64/pci/fixup.c
+++ b/arch/ia64/pci/fixup.c
@@ -5,7 +5,7 @@
#include <linux/pci.h>
#include <linux/init.h>
-#include <linux/vgaarb.h>
+#include <linux/vga_default.h>
#include <linux/screen_info.h>
#include <asm/machvec.h>
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index c95fdda3a2dc..6cfaec107374 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -31,7 +31,7 @@
#include <linux/irq.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
-#include <linux/vgaarb.h>
+#include <linux/vga_default.h>
#include <asm/processor.h>
#include <asm/io.h>
diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c
index 11e407489db0..b1254bc09a45 100644
--- a/arch/x86/pci/fixup.c
+++ b/arch/x86/pci/fixup.c
@@ -5,7 +5,7 @@
#include <linux/delay.h>
#include <linux/dmi.h>
#include <linux/pci.h>
-#include <linux/vgaarb.h>
+#include <linux/vga_default.h>
#include <asm/hpet.h>
#include <asm/pci_x86.h>
diff --git a/arch/x86/video/fbdev.c b/arch/x86/video/fbdev.c
index 9fd24846d094..62cfa74ea86e 100644
--- a/arch/x86/video/fbdev.c
+++ b/arch/x86/video/fbdev.c
@@ -9,7 +9,7 @@
#include <linux/fb.h>
#include <linux/pci.h>
#include <linux/module.h>
-#include <linux/vgaarb.h>
+#include <linux/vga_default.h>
int fb_is_primary_device(struct fb_info *info)
{
diff --git a/drivers/gpu/vga/Kconfig b/drivers/gpu/vga/Kconfig
index 29437eabe095..81d4105aecf6 100644
--- a/drivers/gpu/vga/Kconfig
+++ b/drivers/gpu/vga/Kconfig
@@ -1,3 +1,14 @@
+config VGA_DEFAULT
+ bool "VGA Default Device Support" if EXPERT
+ default y
+ depends on PCI
+ help
+ Some programs find it helpful to know what VGA device is the default.
+ On platforms like x86 this means the device used by the BIOS to show
+ early boot messages. On other platforms this may be an arbitrary PCI
+ graphics card. Select this to have a default device recorded within
+ the kernel and exposed to userspace through sysfs.
+
config VGA_ARB
bool "VGA Arbitration" if EXPERT
default y
@@ -22,6 +33,7 @@ config VGA_SWITCHEROO
depends on X86
depends on ACPI
select VGA_ARB
+ select VGA_DEFAULT
help
Many laptops released in 2008/9/10 have two GPUs with a multiplexer
to switch between them. This adds support for dynamic switching when
diff --git a/drivers/gpu/vga/Makefile b/drivers/gpu/vga/Makefile
index 14ca30b75d0a..1e30f90d40fb 100644
--- a/drivers/gpu/vga/Makefile
+++ b/drivers/gpu/vga/Makefile
@@ -1,2 +1,3 @@
obj-$(CONFIG_VGA_ARB) += vgaarb.o
+obj-$(CONFIG_VGA_DEFAULT) += vga_default.o
obj-$(CONFIG_VGA_SWITCHEROO) += vga_switcheroo.o
diff --git a/drivers/gpu/vga/vga_default.c b/drivers/gpu/vga/vga_default.c
new file mode 100644
index 000000000000..f6fcb0eb1507
--- /dev/null
+++ b/drivers/gpu/vga/vga_default.c
@@ -0,0 +1,159 @@
+/*
+ * vga_default.c: What is the default/boot PCI VGA device?
+ *
+ * (C) Copyright 2005 Benjamin Herrenschmidt <benh at kernel.crashing.org>
+ * (C) Copyright 2007 Paulo R. Zanoni <przanoni at gmail.com>
+ * (C) Copyright 2007, 2009 Tiago Vignatti <vignatti at freedesktop.org>
+ * (C) Copyright 2017 Canonical Ltd. (Author: Daniel Axtens <dja at axtens.net>)
+ *
+ * (License from vgaarb.c)
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+/*
+ * What device should a graphics system draw to? In order of priority:
+ *
+ * 1) Any devices configured specifically by the user (think
+ * xorg.conf).
+ *
+ * 2) If the platform has a concept of a boot device for early boot
+ * messages (think BIOS displays on x86), that device.
+ *
+ * 3) If the platform does not have the concept of a boot device,
+ * then we still want to pick something. For now, pick the first
+ * PCI VGA device with a driver bound and with memory or I/O
+ * control on.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/init.h>
+
+#include <linux/vga_default.h>
+
+static struct pci_dev *vga_default;
+/*
+ * only go active after the late initcall so as not to interfere with
+ * the arbiter
+ */
+static bool vga_default_active = false;
+
+/**
+ * vga_default_device - return the default VGA device
+ *
+ * This can be defined by the platform. The default implementation
+ * is rather dumb and will probably only work properly on single
+ * vga card setups and/or x86 platforms.
+ *
+ * If your VGA default device is not PCI, you'll have to return
+ * NULL here. In this case, I assume it will not conflict with
+ * any PCI card. If this is not true, I'll have to define two archs
+ * hooks for enabling/disabling the VGA default device if that is
+ * possible. This may be a problem with real _ISA_ VGA cards, in
+ * addition to a PCI one. I don't know at this point how to deal
+ * with that card. Can theirs IOs be disabled at all ? If not, then
+ * I suppose it's a matter of having the proper arch hook telling
+ * us about it, so we basically never allow anybody to succeed a
+ * vga_get()...
+ */
+
+struct pci_dev *vga_default_device(void)
+{
+ return vga_default;
+}
+EXPORT_SYMBOL_GPL(vga_default_device);
+
+void vga_set_default_device(struct pci_dev *pdev)
+{
+ if (vga_default == pdev)
+ return;
+
+ pci_dev_put(vga_default);
+ vga_default = pci_dev_get(pdev);
+}
+
+static bool vga_default_try_device(struct pci_dev *pdev)
+{
+ u16 cmd;
+
+ /* Only deal with VGA class devices */
+ if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
+ return false;
+
+ /* Only deal with devices with drivers bound */
+ if (!pdev->driver)
+ return false;
+
+ /* Require I/O or memory control */
+ pci_read_config_word(pdev, PCI_COMMAND, &cmd);
+ if (!(cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)))
+ return false;
+
+ dev_info(&pdev->dev, "vga_default: setting as default device\n");
+ vga_set_default_device(pdev);
+ return true;
+}
+
+static int __init vga_default_init(void)
+{
+ struct pci_dev *pdev;
+
+ vga_default_active = true;
+
+ if (vga_default_device())
+ return 0;
+
+ pdev = NULL;
+ while ((pdev =
+ pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
+ PCI_ANY_ID, pdev)) != NULL) {
+ if (vga_default_try_device(pdev))
+ return 0;
+ }
+
+ return 0;
+}
+late_initcall(vga_default_init);
+
+/*
+ * A driver could be loaded much later than late_initcall, for example
+ * if it's in a module.
+ *
+ * We want to pick that up. However, we want to make sure this does
+ * not interfere with the arbiter - it should only activate if the
+ * arbiter has already had a chance to operate. To ensure this, we set
+ * vga_default_active in the late_initcall: as the vga arbiter is a
+ * subsys initcall, it is guaranteed to fire first.
+ */
+static void vga_default_enable_hook(struct pci_dev *pdev)
+{
+ if (!vga_default_active)
+ return;
+
+ if (vga_default_device())
+ return;
+
+ vga_default_try_device(pdev);
+}
+DECLARE_PCI_FIXUP_CLASS_ENABLE(PCI_ANY_ID, PCI_ANY_ID,
+ PCI_CLASS_DISPLAY_VGA, 8,
+ vga_default_enable_hook)
diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 3cd153c6d271..6612ec7981b6 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -41,7 +41,7 @@
#include <linux/pm_runtime.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
-#include <linux/vgaarb.h>
+#include <linux/vga_default.h>
#include <linux/vga_switcheroo.h>
/**
diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
index 76875f6299b8..74683286f5f8 100644
--- a/drivers/gpu/vga/vgaarb.c
+++ b/drivers/gpu/vga/vgaarb.c
@@ -51,6 +51,7 @@
#include <linux/uaccess.h>
+#include <linux/vga_default.h>
#include <linux/vgaarb.h>
static void vga_arbiter_notify_clients(void);
@@ -119,9 +120,6 @@ static int vga_str_to_iostate(char *buf, int str_size, int *io_state)
return 1;
}
-/* this is only used a cookie - it should not be dereferenced */
-static struct pci_dev *vga_default;
-
static void vga_arb_device_card_gone(struct pci_dev *pdev);
/* Find somebody in our list */
@@ -135,39 +133,6 @@ static struct vga_device *vgadev_find(struct pci_dev *pdev)
return NULL;
}
-/**
- * vga_default_device - return the default VGA device, for vgacon
- *
- * This can be defined by the platform. The default implementation
- * is rather dumb and will probably only work properly on single
- * vga card setups and/or x86 platforms.
- *
- * If your VGA default device is not PCI, you'll have to return
- * NULL here. In this case, I assume it will not conflict with
- * any PCI card. If this is not true, I'll have to define two archs
- * hooks for enabling/disabling the VGA default device if that is
- * possible. This may be a problem with real _ISA_ VGA cards, in
- * addition to a PCI one. I don't know at this point how to deal
- * with that card. Can theirs IOs be disabled at all ? If not, then
- * I suppose it's a matter of having the proper arch hook telling
- * us about it, so we basically never allow anybody to succeed a
- * vga_get()...
- */
-struct pci_dev *vga_default_device(void)
-{
- return vga_default;
-}
-EXPORT_SYMBOL_GPL(vga_default_device);
-
-void vga_set_default_device(struct pci_dev *pdev)
-{
- if (vga_default == pdev)
- return;
-
- pci_dev_put(vga_default);
- vga_default = pci_dev_get(pdev);
-}
-
static inline void vga_irq_set_state(struct vga_device *vgadev, bool state)
{
if (vgadev->irq_set_state)
@@ -667,7 +632,7 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
/* Deal with VGA default device. Use first enabled one
* by default if arch doesn't have it's own hook
*/
- if (vga_default == NULL &&
+ if (vga_default_device() == NULL &&
((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) {
vgaarb_info(&pdev->dev, "setting as boot VGA device\n");
vga_set_default_device(pdev);
@@ -704,7 +669,7 @@ static bool vga_arbiter_del_pci_device(struct pci_dev *pdev)
goto bail;
}
- if (vga_default == pdev)
+ if (vga_default_device() == pdev)
vga_set_default_device(NULL);
if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM))
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 2f3780b50723..c174b427ea2b 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -27,7 +27,7 @@
#include <linux/security.h>
#include <linux/pci-aspm.h>
#include <linux/slab.h>
-#include <linux/vgaarb.h>
+#include <linux/vga_default.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include "pci.h"
diff --git a/include/linux/vga_default.h b/include/linux/vga_default.h
new file mode 100644
index 000000000000..78df6a2a194c
--- /dev/null
+++ b/include/linux/vga_default.h
@@ -0,0 +1,44 @@
+/*
+ * vga_default.h: What is the default/boot PCI VGA device?
+ *
+ * (C) Copyright 2005 Benjamin Herrenschmidt <benh at kernel.crashing.org>
+ * (C) Copyright 2007 Paulo R. Zanoni <przanoni at gmail.com>
+ * (C) Copyright 2007, 2009 Tiago Vignatti <vignatti at freedesktop.org>
+ * (C) Copyright 2017 Canonical Ltd. (Author: Daniel Axtens <dja at axtens.net>)
+ *
+ * (License from vgaarb.h)
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef LINUX_VGA_DEFAULT_H
+#define LINUX_VGA_DEFAULT_H
+
+struct pci_dev;
+
+#ifdef CONFIG_VGA_DEFAULT
+extern struct pci_dev *vga_default_device(void);
+extern void vga_set_default_device(struct pci_dev *pdev);
+#else
+static inline struct pci_dev *vga_default_device(void) { return NULL; };
+static inline void vga_set_default_device(struct pci_dev *pdev) { };
+#endif
+
+#endif
diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h
index ee162e3e879b..953e1955efbe 100644
--- a/include/linux/vgaarb.h
+++ b/include/linux/vgaarb.h
@@ -42,12 +42,6 @@
#define VGA_RSRC_NORMAL_IO 0x04
#define VGA_RSRC_NORMAL_MEM 0x08
-/* Passing that instead of a pci_dev to use the system "default"
- * device, that is the one used by vgacon. Archs will probably
- * have to provide their own vga_default_device();
- */
-#define VGA_DEFAULT_DEVICE (NULL)
-
struct pci_dev;
/* For use by clients */
@@ -122,14 +116,6 @@ extern void vga_put(struct pci_dev *pdev, unsigned int rsrc);
#endif
-#ifdef CONFIG_VGA_ARB
-extern struct pci_dev *vga_default_device(void);
-extern void vga_set_default_device(struct pci_dev *pdev);
-#else
-static inline struct pci_dev *vga_default_device(void) { return NULL; };
-static inline void vga_set_default_device(struct pci_dev *pdev) { };
-#endif
-
/*
* Architectures should define this if they have several
* independent PCI domains that can afford concurrent VGA
--
2.11.0
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