linux/drivers/gpu/drm/i915/Kconfig.debug
Daniel Vetter 7e8376f1d1 drm/i915: Improve debug Kconfig texts a bit
We're not consistently recommending these for developers only.

I stumbled over this due to DRM_I915_LOW_LEVEL_TRACEPOINTS, which was
added in

commit 354d036fcf
Author: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Date:   Tue Feb 21 11:01:42 2017 +0000

    drm/i915/tracepoints: Add request submit and execute tracepoints

to "alleviate the performance impact concerns."

Which is nonsense.

Tvrtko and Joonas pointed out on irc that the real (but undocumented
reason) was stable abi concerns for tracepoints, see

https://lwn.net/Articles/705270/

and the specific change that was blocked around tracepoints:

https://lwn.net/Articles/442113/

Anyway to make it a notch clearer why we have this Kconfig option
consistly add the "Recommended for driver developers only." to it and
all the other debug options we have.

Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210702201708.2075793-1-daniel.vetter@ffwll.ch
2021-07-06 10:10:07 +02:00

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7.0 KiB
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# SPDX-License-Identifier: GPL-2.0-only
config DRM_I915_WERROR
bool "Force GCC to throw an error instead of a warning when compiling"
# As this may inadvertently break the build, only allow the user
# to shoot oneself in the foot iff they aim really hard
depends on EXPERT
# We use the dependency on !COMPILE_TEST to not be enabled in
# allmodconfig or allyesconfig configurations
depends on !COMPILE_TEST
default n
help
Add -Werror to the build flags for (and only for) i915.ko.
Do not enable this unless you are writing code for the i915.ko module.
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_DEBUG
bool "Enable additional driver debugging"
depends on DRM_I915
depends on EXPERT # only for developers
depends on !COMPILE_TEST # never built by robots
select DEBUG_FS
select PREEMPT_COUNT
select I2C_CHARDEV
select STACKDEPOT
select DRM_DP_AUX_CHARDEV
select X86_MSR # used by igt/pm_rpm
select DRM_VGEM # used by igt/prime_vgem (dmabuf interop checks)
select DRM_DEBUG_MM if DRM=y
select DRM_EXPORT_FOR_TESTS if m
select DRM_DEBUG_SELFTEST
select DMABUF_SELFTESTS
select SW_SYNC # signaling validation framework (igt/syncobj*)
select DRM_I915_WERROR
select DRM_I915_DEBUG_GEM
select DRM_I915_DEBUG_GEM_ONCE
select DRM_I915_DEBUG_MMIO
select DRM_I915_DEBUG_RUNTIME_PM
select DRM_I915_SW_FENCE_DEBUG_OBJECTS
select DRM_I915_SELFTEST
default n
help
Choose this option to turn on extra driver debugging that may affect
performance but will catch some internal issues.
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_DEBUG_MMIO
bool "Always insert extra checks around mmio access by default"
default n
help
By default, always enables the extra sanity checks (extra register
reads) around every mmio (register) access that will slow the system
down. This sets the default value of i915.mmio_debug to -1 and can
be overridden at module load.
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_DEBUG_GEM
bool "Insert extra checks into the GEM internals"
default n
depends on DRM_I915_WERROR
help
Enable extra sanity checks (including BUGs) along the GEM driver
paths that may slow the system down and if hit hang the machine.
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_DEBUG_GEM_ONCE
bool "Make a GEM debug failure fatal"
default n
depends on DRM_I915_DEBUG_GEM
help
During development, we often only want the very first failure
as that would otherwise be lost in the deluge of subsequent
failures. However, more casual testers may not want to trigger
a hard BUG_ON and hope that the system remains sufficiently usable
to capture a bug report in situ.
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_ERRLOG_GEM
bool "Insert extra logging (very verbose) for common GEM errors"
default n
depends on DRM_I915_DEBUG_GEM
help
Enable additional logging that may help track down the cause of
principally userspace errors.
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_TRACE_GEM
bool "Insert extra ftrace output from the GEM internals"
depends on DRM_I915_DEBUG_GEM
select TRACING
default n
help
Enable additional and verbose debugging output that will spam
ordinary tests, but may be vital for post-mortem debugging when
used with /proc/sys/kernel/ftrace_dump_on_oops
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_TRACE_GTT
bool "Insert extra ftrace output from the GTT internals"
depends on DRM_I915_DEBUG_GEM
select TRACING
default n
help
Enable additional and verbose debugging output that will spam
ordinary tests, but may be vital for post-mortem debugging when
used with /proc/sys/kernel/ftrace_dump_on_oops
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_SW_FENCE_DEBUG_OBJECTS
bool "Enable additional driver debugging for fence objects"
depends on DRM_I915
select DEBUG_OBJECTS
default n
help
Choose this option to turn on extra driver debugging that may affect
performance but will catch some internal issues.
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_SW_FENCE_CHECK_DAG
bool "Enable additional driver debugging for detecting dependency cycles"
depends on DRM_I915
default n
help
Choose this option to turn on extra driver debugging that may affect
performance but will catch some internal issues.
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_DEBUG_GUC
bool "Enable additional driver debugging for GuC"
depends on DRM_I915
default n
help
Choose this option to turn on extra driver debugging that may affect
performance but will help resolve GuC related issues.
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_SELFTEST
bool "Enable selftests upon driver load"
depends on DRM_I915
default n
select DRM_EXPORT_FOR_TESTS if m
select FAULT_INJECTION
select PRIME_NUMBERS
select CRC32
help
Choose this option to allow the driver to perform selftests upon
loading; also requires the i915.selftest=1 module parameter. To
exit the module after running the selftests (i.e. to prevent normal
module initialisation afterwards) use i915.selftest=-1.
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_SELFTEST_BROKEN
bool "Enable broken and dangerous selftests"
depends on DRM_I915_SELFTEST
depends on BROKEN
default n
help
This option enables the execution of selftests that are "dangerous"
and may trigger unintended HW side-effects as they break strict
rules given in the HW specification. For science.
Recommended for masochistic driver developers only.
If in doubt, say "N".
config DRM_I915_LOW_LEVEL_TRACEPOINTS
bool "Enable low level request tracing events"
depends on DRM_I915
default n
help
Choose this option to turn on low level request tracing events.
This provides the ability to precisely monitor engine utilisation
and also analyze the request dependency resolving timeline.
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_DEBUG_VBLANK_EVADE
bool "Enable extra debug warnings for vblank evasion"
depends on DRM_I915
default n
help
Choose this option to turn on extra debug warnings for the
vblank evade mechanism. This gives a warning every time the
the deadline allotted for the vblank evade critical section
is exceeded, even if there isn't an actual risk of missing
the vblank.
Recommended for driver developers only.
If in doubt, say "N".
config DRM_I915_DEBUG_RUNTIME_PM
bool "Enable extra state checking for runtime PM"
depends on DRM_I915
default n
select STACKDEPOT
help
Choose this option to turn on extra state checking for the
runtime PM functionality. This may introduce overhead during
driver loading, suspend and resume operations.
Recommended for driver developers only.
If in doubt, say "N"