linux_dsm_epyc7002/drivers/gpu/drm/i915/Kconfig
Chris Wilson 5bab6f60cb drm/i915: Serialise updates to GGTT with access through GGTT on Braswell
When accessing through the GTT from one CPU whilst concurrently updating
the GGTT PTEs in another thread, the hardware likes to return random
data. As we have strong serialisation prevent us from modifying the PTE
of an active GTT mmapping, we have to conclude that it whilst modifying
other PTE's that error occurs. (I have not looked for any pattern such
as modifying PTE within the same page or cacheline as active PTE -
though checking whether revoking neighbouring objects should be enough
to test that theory.) The corruption also seems restricted to Braswell
and disappears with maxcpus=0. This patch stops all access through the
GTT by other CPUs when we update any PTE by stopping the machine around
the GGTT update.

Note that splitting up the 64 bit write into two 32 bit writes was
tried and found to fail too.

Testcase: igt/gem_concurrent_blit
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89079
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Add note about 2x 32bits failing too.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-11-17 17:36:01 +01:00

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config DRM_I915
tristate "Intel 8xx/9xx/G3x/G4x/HD Graphics"
depends on DRM
depends on X86 && PCI
depends on (AGP || AGP=n)
select INTEL_GTT
select AGP_INTEL if AGP
select INTERVAL_TREE
# we need shmfs for the swappable backing store, and in particular
# the shmem_readpage() which depends upon tmpfs
select SHMEM
select TMPFS
select STOP_MACHINE
select DRM_KMS_HELPER
select DRM_PANEL
select DRM_MIPI_DSI
# i915 depends on ACPI_VIDEO when ACPI is enabled
# but for select to work, need to select ACPI_VIDEO's dependencies, ick
select BACKLIGHT_LCD_SUPPORT if ACPI
select BACKLIGHT_CLASS_DEVICE if ACPI
select INPUT if ACPI
select ACPI_VIDEO if ACPI
select ACPI_BUTTON if ACPI
help
Choose this option if you have a system that has "Intel Graphics
Media Accelerator" or "HD Graphics" integrated graphics,
including 830M, 845G, 852GM, 855GM, 865G, 915G, 945G, 965G,
G35, G41, G43, G45 chipsets and Celeron, Pentium, Core i3,
Core i5, Core i7 as well as Atom CPUs with integrated graphics.
If M is selected, the module will be called i915. AGP support
is required for this driver to work. This driver is used by
the Intel driver in X.org 6.8 and XFree86 4.4 and above. It
replaces the older i830 module that supported a subset of the
hardware in older X.org releases.
Note that the older i810/i815 chipsets require the use of the
i810 driver instead, and the Atom z5xx series has an entirely
different implementation.
config DRM_I915_PRELIMINARY_HW_SUPPORT
bool "Enable preliminary support for prerelease Intel hardware by default"
depends on DRM_I915
default n
help
Choose this option if you have prerelease Intel hardware and want the
i915 driver to support it by default. You can enable such support at
runtime with the module option i915.preliminary_hw_support=1; this
option changes the default for that module option.
If in doubt, say "N".