Commit Graph

11 Commits

Author SHA1 Message Date
Bjorn Helgaas f321c35fea PCI/VGA: Replace full MIT license text with SPDX identifier
Per Documentation/process/license-rules.rst, the SPDX MIT identifier is
equivalent to including the entire MIT license text from
LICENSES/preferred/MIT.

Replace the MIT license text with the equivalent SPDX identifier.

Link: https://lore.kernel.org/r/20220224224753.297579-12-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2022-03-09 18:31:34 -06:00
Bjorn Helgaas d5109fe4d1 PCI/VGA: Use unsigned format string to print lock counts
In struct vga_device, io_lock_cnt and mem_lock_cnt are unsigned, but we
previously printed them with "%d", the signed decimal format.  Print them
with the unsigned format "%u" instead.

Link: https://lore.kernel.org/r/20220224224753.297579-11-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2022-03-09 18:31:32 -06:00
Huacai Chen 4e6c91847a PCI/VGA: Log bridge control messages when adding devices
Previously vga_arb_device_init() iterated through all VGA devices and
indicated whether legacy VGA routing to each could be controlled by an
upstream bridge.

But we determine that information in vga_arbiter_add_pci_device(), which we
call for every device, so we can log it there without iterating through the
VGA devices again.

Note that we call vga_arbiter_check_bridge_sharing() before adding the
device to vga_list, so we have to handle the very first device separately.

Link: https://lore.kernel.org/r/20220224224753.297579-10-helgaas@kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2022-03-09 18:31:28 -06:00
Bjorn Helgaas dc593fd48a PCI/VGA: Remove empty vga_arb_device_card_gone()
vga_arb_device_card_gone() has always been empty.  Remove it.

Link: https://lore.kernel.org/r/20220224224753.297579-9-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2022-03-09 18:31:24 -06:00
Huacai Chen 37114e4d15 PCI/VGA: Move disabled VGA device detection to ADD_DEVICE path
a37c0f4895 ("vgaarb: Select a default VGA device even if there's no
legacy VGA") extended the vga_arb_device_init() subsys_initcall so that if
there are no other eligible devices, it could select a disabled VGA device
as the default.

Move this detection from vga_arb_select_default_device() to
vga_arbiter_add_pci_device() so every device, even those hot-added or
enumerated after vga_arb_device_init() is eligible for selection as the
default VGA device.

[bhelgaas: commit log, restructure]
Link: https://lore.kernel.org/r/20211015061512.2941859-5-chenhuacai@loongson.cn
Link: https://lore.kernel.org/r/20220224224753.297579-8-helgaas@kernel.org
Signed-off-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Zhou Wang <wangzhou1@hisilicon.com>
2022-03-09 18:31:19 -06:00
Huacai Chen e96902eb8c PCI/VGA: Move non-legacy VGA detection to ADD_DEVICE path
a37c0f4895 ("vgaarb: Select a default VGA device even if there's no
legacy VGA") extended the vga_arb_device_init() subsys_initcall so it could
select a non-legacy VGA device as the default.

That failed to consider that PCI devices may be enumerated after
vga_arb_device_init(), e.g., hot-added devices or non-ACPI systems that do
PCI enumeration in pcibios_init().  Devices found then could never be
selected as the default.

One system where this is a problem is the MIPS-based Loongson where an
ASpeed AST2500 VGA device is behind a bridge that doesn't implement the VGA
Enable bit, so legacy resources are not routed to the VGA device. [1]

Fix this by moving the non-legacy VGA device selection from
vga_arb_select_default_device() to vga_arbiter_add_pci_device(), which is
called after every PCI device is enumerated, either by the
vga_arb_device_init() subsys_initcall or as an ADD_DEVICE notifier.

[1] https://lore.kernel.org/r/20210514080025.1828197-6-chenhuacai@loongson.cn

[bhelgaas: commit log, restructure]
Link: https://lore.kernel.org/r/20211015061512.2941859-5-chenhuacai@loongson.cn
Link: https://lore.kernel.org/r/20211015061512.2941859-7-chenhuacai@loongson.cn
Link: https://lore.kernel.org/r/20220224224753.297579-7-helgaas@kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Zhou Wang <wangzhou1@hisilicon.com>
2022-03-09 18:31:14 -06:00
Huacai Chen f8d81df285 PCI/VGA: Move firmware default device detection to ADD_DEVICE path
Previously we selected the firmware default device, i.e., one that owns the
boot framebuffer, as the default device in vga_arb_select_default_device().
This was only done in the vga_arb_device_init() subsys_initcall, so devices
enumerated later, e.g., by pcibios_init(), were not eligible.

Fix this by moving the firmware default device selection from
vga_arb_select_default_device() to vga_arbiter_add_pci_device(), which is
called after every PCI device is enumerated, either by the
vga_arb_device_init() subsys_initcall or as an ADD_DEVICE notifier.

Note that if vga_arb_select_default_device() previously found a device
owning the boot framebuffer, it unconditionally set it to be the default
VGA device, and no subsequent device could replace it.

[bhelgaas: commit log, restructure slightly]
Link: https://lore.kernel.org/r/20211015061512.2941859-7-chenhuacai@loongson.cn
Link: https://lore.kernel.org/r/20220224224753.297579-6-helgaas@kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Bruno Prémont <bonbons@linux-vserver.org>
2022-03-09 18:31:08 -06:00
Huacai Chen dfe3da812d PCI/VGA: Factor out default VGA device selection
Default VGA device selection fails when PCI devices are enumerated after
the vga_arb_device_init() subsys_initcall.

vga_arbiter_add_pci_device() selects the first fully enabled device to
which legacy VGA resources are routed as the default VGA device.  This is
an ADD_DEVICE notifier, so it runs after every PCI device is enumerated.

vga_arb_select_default_device() may select framebuffer devices, partially
enabled GPUs, or non-legacy devices that don't have legacy VGA resources
routed to them as the default VGA device.  But this only happens once, from
the vga_arb_device_init() subsys_initcall, so it doesn't consider devices
enumerated after that:

  acpi_init
    acpi_scan_init
      acpi_pci_root_init         # PCI device enumeration (ACPI systems)

  vga_arb_device_init
    for_each_pci_device
      vga_arbiter_add_pci_device      # ADD_DEVICE notifier
        if (VGA-owner)
          vga_set_default_device      <-- set default VGA
    vga_arb_select_default_device     # only called ONCE
      for_each_vga_device
        if (framebuffer)
          vga_set_default_device      <-- set default VGA to framebuffer
      if (!vga_default_device())
        if (non-legacy, integrated GPU, etc)
          vga_set_default_device      <-- set default VGA
      if (!vga_default_device())
        vga_set_default_device        <-- set default VGA

  pcibios_init
    pcibios_scanbus              # PCI device enumeration (non-ACPI systems)
      ...
        vga_arbiter_add_pci_device    # ADD_DEVICE notification
          if (VGA-owner)
            vga_set_default_device    <-- set default VGA

Note that on non-ACPI systems, vga_arb_select_default_device() runs before
pcibios_init(), so it sees no VGA devices and can never set a framebuffer
device, a non-legacy integrated GPU, etc., as the default device.

Factor out the default VGA device selection to vga_is_boot_device(), called
from vga_arbiter_add_pci_device().

Then we can migrate the default device selection from
vga_arb_select_default_device() to the vga_arbiter_add_pci_device() path.

[bhelgaas: commit log, split to separate patch]
Link: https://lore.kernel.org/r/20211015061512.2941859-4-chenhuacai@loongson.cn
Link: https://lore.kernel.org/r/20220224224753.297579-5-helgaas@kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2022-03-09 18:31:02 -06:00
Bjorn Helgaas 60a9bac8ab PCI/VGA: Factor out vga_select_framebuffer_device()
On x86 and ia64, if a VGA device BARs include a framebuffer reported by
platform firmware, we select the device as the default VGA device.  Factor
this code to a separate function.  No functional change intended.

Link: https://lore.kernel.org/r/20220224224753.297579-4-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Bruno Prémont <bonbons@linux-vserver.org>
2022-03-09 18:30:56 -06:00
Huacai Chen c1593ddd89 PCI/VGA: Move vga_arb_integrated_gpu() earlier in file
Move vga_arb_integrated_gpu() earlier in file to prepare for future patch.
No functional change intended.

[bhelgaas: pull #ifdefs inside function]
Link: https://lore.kernel.org/r/20211015061512.2941859-3-chenhuacai@loongson.cn
Link: https://lore.kernel.org/r/20220224224753.297579-3-helgaas@kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2022-03-09 18:30:48 -06:00
Bjorn Helgaas 1d38fe6ee6 PCI/VGA: Move vgaarb to drivers/pci
The VGA arbiter is really PCI-specific and doesn't depend on any GPU
things.  Move it to the PCI subsystem.

Note that misc_init() must be called before vga_arb_device_init().  These
are both subsys_initcalls, so this ordering depends on the link order,
which is determined by drivers/Makefile:

  obj-y += pci/
  obj-y += char/        <-- misc_init()
  obj-y += gpu/         <-- vga_arb_device_init() (before this commit)

The drivers/pci/ subsys_initcalls are called *before* misc_init(), so
convert vga_arb_device_init() to subsys_initcall_sync(), which is called
after *all* subsys_initcalls.

Link: https://lore.kernel.org/r/20220224224753.297579-2-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2022-03-09 18:30:46 -06:00