linux_dsm_epyc7002/drivers
Bjorn Helgaas a37c0f4895 vgaarb: Select a default VGA device even if there's no legacy VGA
Daniel Axtens reported that on the HiSilicon D05 board, the VGA device is
behind a bridge that doesn't support PCI_BRIDGE_CTL_VGA, so the VGA arbiter
never selects it as the default, which means Xorg auto-detection doesn't
work.

VGA is a legacy PCI feature: a VGA device can respond to addresses, e.g.,
[mem 0xa0000-0xbffff], [io 0x3b0-0x3bb], [io 0x3c0-0x3df], etc., that are
not configurable by BARs.  Consequently, multiple VGA devices can conflict
with each other.  The VGA arbiter avoids conflicts by ensuring that those
legacy resources are only routed to one VGA device at a time.

The arbiter identifies the "default VGA" device, i.e., a legacy VGA device
that was used by boot firmware.  It selects the first device that:

  - is of PCI_CLASS_DISPLAY_VGA,
  - has both PCI_COMMAND_IO and PCI_COMMAND_MEMORY enabled, and
  - has PCI_BRIDGE_CTL_VGA set in all upstream bridges.

Some systems don't have such a device.  For example, if a host bridge
doesn't support I/O space, PCI_COMMAND_IO probably won't be enabled for any
devices below it.  Or, as on the HiSilicon D05, the VGA device may be
behind a bridge that doesn't support PCI_BRIDGE_CTL_VGA, so accesses to the
legacy VGA resources will never reach the device.

This patch extends the arbiter so that if it doesn't find a device that
meets all the above criteria, it selects the first device that:

  - is of PCI_CLASS_DISPLAY_VGA and
  - has PCI_COMMAND_IO or PCI_COMMAND_MEMORY enabled

If it doesn't find even that, it selects the first device that:

  - is of class PCI_CLASS_DISPLAY_VGA.

Such a device may not be able to use the legacy VGA resources, but most
drivers can operate the device without those.  Setting it as the default
device means its "boot_vga" sysfs file will contain "1", which Xorg (via
libpciaccess) uses to help select its default output device.

This fixes Xorg auto-detection on some arm64 systems (HiSilicon D05 in
particular; see the link below).

It also replaces the powerpc fixup_vga() quirk, albeit with slightly
different semantics: the quirk selected the first VGA device we found, and
overrode that selection with any enabled VGA device we found.  If there
were several enabled VGA devices, the *last* one we found would become the
default.

The code here instead selects the *first* enabled VGA device we find, and
if none are enabled, the first VGA device we find.

Link: http://lkml.kernel.org/r/20170901072744.2409-1-dja@axtens.net
Tested-by: Daniel Axtens <dja@axtens.net>       # arm64, ppc64-qemu-tcg
Tested-by: Zhou Wang <wangzhou1@hisilicon.com>  # D05 Hisi Hip07, Hip08
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171013034721.14630.65913.stgit@bhelgaas-glaptop.roam.corp.google.com
2017-10-18 10:04:56 +02:00
..
accessibility
acpi Merge branch 'acpi-apei' 2017-09-28 22:18:15 +02:00
amba
android
ata
atm
auxdisplay
base PM / OPP: Call notifier without holding opp_table->lock 2017-09-26 00:44:32 +02:00
bcma
block loop: remove union of use_aio and ref in struct loop_cmd 2017-09-25 08:56:05 -06:00
bluetooth
bus
cdrom
char Merge branch 'next-tpm' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2017-09-24 11:34:28 -07:00
clk
clocksource x86/numachip: Add const and __initconst to numachip2_clockevent 2017-09-25 09:36:15 +02:00
connector
cpufreq cpufreq: dt: Fix sysfs duplicate filename creation for platform-device 2017-09-26 01:10:08 +02:00
cpuidle ARM: cpuidle: Avoid memleak if init fail 2017-09-19 23:10:51 +02:00
crypto crypto: caam - fix LS1021A support on ARMv7 multiplatform kernel 2017-09-20 17:42:42 +08:00
dax
dca
devfreq
dio
dma
dma-buf dma-buf: make reservation_object_copy_fences rcu save 2017-10-09 11:07:56 -04:00
edac
eisa
extcon
firewire
firmware
fmc
fpga
fsi
gpio
gpu vgaarb: Select a default VGA device even if there's no legacy VGA 2017-10-18 10:04:56 +02:00
hid
hsi
hv
hwmon
hwspinlock
hwtracing
i2c
ide
idle
iio
infiniband IB/hfi1: Unsuccessful PCIe caps tuning should not fail driver load 2017-09-27 11:10:36 -04:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2017-09-22 17:23:41 -10:00
iommu iommu/amd: pr_err() strings should end with newlines 2017-09-27 17:01:35 +02:00
ipack
irqchip irqchip/mips-gic: Use effective affinity to unmask 2017-09-25 21:23:44 +02:00
isdn isdn/i4l: fetch the ppp_write buffer in one shot 2017-09-20 16:01:36 -07:00
leds as3645a: Unregister indicator LED on device unbind 2017-09-23 21:17:43 +02:00
lightnvm
macintosh
mailbox
mcb
md md/raid5: cap worker count 2017-09-27 20:08:44 -07:00
media
memory
memstick
message
mfd
misc
mmc MMC host: 2017-09-26 16:54:22 -07:00
mtd mtd: nand: atmel: fix buffer overflow in atmel_pmecc_user 2017-09-27 17:33:28 +02:00
mux
net net: phy: Fix truncation of large IRQ numbers in phy_attached_print() 2017-09-21 20:35:17 -07:00
nfc
ntb
nubus
nvdimm libnvdimm, namespace: fix btt claim class crash 2017-09-18 17:29:01 -07:00
nvme nvme-fcloop: fix port deletes and callbacks 2017-09-25 12:42:11 -06:00
nvmem
of
oprofile
parisc
parport
pci PCI: Fix race condition with driver_override 2017-09-25 18:34:54 -05:00
pcmcia
perf drivers/perf: arm_pmu_acpi: Release memory obtained by kasprintf 2017-09-22 15:11:46 +01:00
phy Merge branch '4.14-features' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2017-09-15 20:43:33 -07:00
pinctrl
platform platform/x86: fujitsu-laptop: Don't oops when FUJ02E3 is not presnt 2017-09-27 00:04:43 -07:00
pnp
power
powercap
pps
ps3
ptp
pwm
rapidio
ras
regulator
remoteproc
reset Merge branch '4.14-features' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2017-09-15 20:43:33 -07:00
rpmsg
rtc
s390 s390/cio: recover from bad paths 2017-09-19 08:36:19 +02:00
sbus
scsi SCSI fixes on 20170930 2017-09-30 12:50:56 -07:00
sfi
sh
sn
soc Merge branch '4.14-features' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2017-09-15 20:43:33 -07:00
spi
spmi
ssb
staging
target
tc
tee
thermal
thunderbolt
tty
uio
usb
uwb
vfio
vhost
video
virt
virtio
vlynq
vme
w1
watchdog Merge branch '4.14-features' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2017-09-15 20:43:33 -07:00
xen xen: fixes for 4.14-rc3 2017-09-29 12:24:28 -07:00
zorro
Kconfig
Makefile