This reverts commit f6893fcb10.
[WHY & HOW]
The writeback series cause a regression in thunderbolt display.
Signed-off-by: Alex Hung <alex.hung@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This reverts commit 428542d917.
[WHY & HOW]
The writeback series cause a regression in thunderbolt display.
Signed-off-by: Alex Hung <alex.hung@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This reverts commit b79a00a4d4.
[WHY & HOW]
The writeback series cause a regression in thunderbolt display.
Signed-off-by: Alex Hung <alex.hung@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This reverts commit 77a66faacc.
[WHY & HOW]
The writeback series cause a regression in thunderbolt display.
Signed-off-by: Alex Hung <alex.hung@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This reverts commit c4c182b548.
After this was commit PCON and USB4 issues were observed. A new fix will
be submitted instead.
Signed-off-by: Alex Hung <alex.hung@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
As dc_set_power_state() no longer allocates memory, it's not necessary
to have return types and check return code as it can't fail anymore.
Change it back to `void`.
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
If there is memory pressure at suspend time then dynamically
allocating a large structure as part of DC suspend code will
fail.
Instead re-use the same structures and clear all members except
those that should be maintained.
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2362
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm_atomic_helper_suspend() can return PTR_ERR(), in which case the
error gets stored into `dm->cached_state`. This can cause failures
during resume. Catch the error during suspend and fail the suspend
instead.
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2362
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why]
eDPs fail to light up with seamless boot enabled
[How]
When seamless boot is enabled don't configure dpms_off
in disable_vbios_mode_if_required.
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Daniel Miess <daniel.miess@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This version brings along following fixes:
- Refactor DPG test pattern logic for ODM cases
- Refactor HWSS into component folder
- Revert "drm/amd/display: Add a check for idle power optimization"
- Revert "drm/amd/display: remove duplicated edp relink to fastboot
- Update cursor limits based on SW cursor fallback limits
- Update stream mask
- Update pmfw_driver_if new structure
- Modify SMU message logs
- Don't set dpms_off for seamless boot
Known issue:
DWB (Writeback functionality) is broken.
Fix will be available in DC 3.2.256
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why]
This could work around the issue with DP tunneling producing
a NULL pointer dereference.
[How]
Disable the virtual links.
Reviewed-by: Tom Chung <chiahsuan.chung@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Stylon Wang <stylon.wang@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why]
Enabling DPG causes HUBP to stay in blank constantly. If DPG is enabled
while an MCLK switch is taking place with SubVP, it will cause the MCLK
to never complete. This is because SubVP MCLK switch relies a HUBP
VLine interrupt, which will never occur when HUBP is constantly in
blank.
[How]
Disable SubVP when test pattern is enabled.
Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Reviewed-by: Nevenko Stupar <nevenko.stupar@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: George Shen <george.shen@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why]
Current DPG test pattern logic does not account for ODM configuration
changes after test pattern has already been programmed. For example, if
ODM2:1 is enabled after test pattern is already being output, the second
pipe is not programmed to output test pattern, causing half the screen
to be black.
[How]
Move DPG test pattern parameter calculations into separate function.
Whenever ODM pipe configuration changes, re-calculate DPG test pattern
parameters and program DPG if test pattern is currently enabled.
Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: George Shen <george.shen@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why]
eDPs fail to light up with seamless boot enabled
[How]
When seamless boot is enabled don't configure dpms_off
in disable_vbios_mode_if_required.
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Daniel Miess <daniel.miess@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[why]
Rename hw_sequencer to hwseq.
Move all hwseq files to unique
folder hwss.
[how]
creating hwss repo in dc, and moved the dcnxx_hwseq.c
and .h files into corresponding new folders inside the hwss
and cleared the linkage errors by adding relative paths
in the Makefile.template.
Reviewed-by: Martin Leung <martin.leung@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Mounika Adhuri <moadhuri@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Revert commit 434cf7af49 ("drm/amd/display: Add a check for idle power optimization")
Because it cause Freesync and S4 regression
Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Sung Joon Kim <sungkim@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why]
These functions can be called from high IRQ levels and the OS will hang
if it tries to use a usleep_highres or a msleep.
[How]
Replace the fsleep with a udelay.
Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why&How]
For determining the cursor size limit, use the same checks that
are used for determining SW cursor fallback instead of only
using SubVP
Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Alvin Lee <alvin.lee2@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[why]
Need to use real clock table
[How]
Update the clock table
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Muhammad Ahmed <ahmed.ahmed@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why]
Whenever stream changes because of new
pipe arrangements such as ODM. The new
stream mask is not reflected in DMCUB.
The mismatch in stream mask is blocking ips
entry in some scenarios.
[How]
Whenever stream arrangement changes,
update stream mask and notify DMCUB.
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Duncan Ma <duncan.ma@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Revert commit 984abb5384 ("drm/amd/display: remove duplicated edp relink to fastboot")
Because it cause 4k EDP not light up on boot
Reviewed-by: Tom Chung <chiahsuan.chung@amd.com>
Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Fine tune the Vmin clock value
Reviewed-by: Robin Chen <robin.chen@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Max Tseng <max.tseng@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[why]
pmfw header file updated, need align with data structure.
[How]
Update the data structure.
Reviewed-by: Sung joon Kim <sungjoon.kim@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Charlene Liu <charlene.liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[WHY]
FreeSync spec requires PB8 and PB12 to be set to nominal
refresh rate regardless of fixed rate or variable
[HOW]
Removed the condition that checks and overwrites max refresh rate
and set PB8/PB12 to be set to max refresh rate always
Reviewed-by: Anthony Koo <anthony.koo@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Muhammad Ansari <muhammad.ansari@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[why]
It's important to make sure SMU messages
are logged by default to improve debugging for
power optimization use cases.
[how]
Change logs to warnings when SMU message
returns non-success id.
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Sung Joon Kim <sungkim@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
With S/G display becomes stable, enable S/G display for recent APUs
by default rather than white list.
v2: explicitly disable sg on pre-CZ chips (Alex)
v3: add parens for every clause (Alex)
Co-authored-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Yifan Zhang <yifan1.zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[what]
does_configuration_meet_sw_policies check was not done in the
validate_only portion of dml2, so some unsupported modes were passing bw
validation, only to fail the same check later in validate_and_build. now
we add the check to validate_only.
Also add line in dcn35_resource to ensure that value set for
enable_windowed_mpo_odm gets passed to dml.
[why]
Immediate black screen during video playback at 4k144hz. The debugger
showed that we were failing validation in dml on every updateplanes().
Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Signed-off-by: Gabe Teeger <gabe.teeger@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Update DML2 with replay vblank logic found in DML1.
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Daniel Miess <daniel.miess@amd.com>
Signed-off-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why]
There are certain cases during a transition to ODM that might cause
corruption on the display. This occurs when we choose certain pipes in a
particular state.
[How]
We now will store the pipe indexes of the any pipes that might be
problematic to switch to during an ODM transition, and only use them as
a last resort.
Reviewed-by: Dmytro Laktyushkin <dmytro.laktyushkin@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Signed-off-by: Saaem Rizvi <syedsaaem.rizvi@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
dc->dml2_options.use_native_pstate_optimization flag will make driver
use dcn32 legacy_svp_drr related tuning. Set this to false fixed the
stutter underflow issue also based on HW suggest disable ODM by default
and let DML choose it.
Reviewed-by: Zhan Liu <zhan.liu@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Signed-off-by: Charlene Liu <charlene.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[why]
Surface height/width for Chroma has another variable that it should be
intialized to, chroma_size. Fixing this will help pass DML2.0 validation
for YCbCr420 tests, DCHB006.109,129, DCHB014.011,012.
[how]
Assign SurfaceHeight/WidthC to chroma_size.height/width
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Sung Joon Kim <sungkim@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why & How]
DML2 did not carry over DML1 logic that splits pipe for stero timings. Pipe
splitting is needed in this case to pass stereo tests.
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Signed-off-by: Taimur Hassan <syed.hassan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[why]
Regression from DML1.0 where we use differen DET buffer sizes for each
pipe. From the spec, we need to use DET buffer size of 384 kb for each
pipe
[how]
Ensure to use 384 kb DET buffer sizes for each available pipe.
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Sung Joon Kim <sungkim@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[why]
There are cases where more than 1 stream can be mapped to the same
surface. DML2.0 does not seem to handle these cases.
[how]
Make sure to account for the stream id when deriving the plane id. By
doing this, each plane id will be unique based on the stream id.
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Sung Joon Kim <sungkim@amd.com>
Signed-off-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Add z8 watermarks to struct for later ASIC use.
Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Charlene Liu <charlene.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Enable DML2 for DCN35.
Changes since V1:
- Remove hard coded values
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Signed-off-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
DC is transitioning from DML to DML2, and this commit introduces all the
required changes for some of the already available ASICs and adds the
required code infra to support new ASICs under DML2. DML2 is also a
generated code that provides better mode verification and programming
models for software/hardware, and it enables a better way to create
validation tools. This version is more like a middle step to the
complete transition to the DML2 version.
Changes since V1:
- Alex: Fix typos
Changes since V2:
- Update DC includes
Changes since V3:
- Fix 32 bit compilation issues on x86
Changes since V4:
- Avoid compilation of DML2 on some not supported 32-bit architecture
- Update commit message
Co-developed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Co-developed-by: Roman Li <roman.li@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Signed-off-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
For some reason, the dml code is not guarded under CONFIG_DRM_AMD_DC_FP
in the Makefile. This commit moves the dml code under the DC_FP guard.
Reviewed-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
bw_fixed does not need any FPU operation, and it is used on DCE and DCN.
For this reason, this commit moves bw_fixed to the basic folder outside
DML.
Reviewed-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
The custom_float file does not have any FPU operation, so it should be
inside DML. This commit moves the file to the basic folder.
Reviewed-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
dce_calcs does not have FPU operations, and it is required for DCE and
DCN. Remove this file from the DML folder and add it to the basic folder
visible for DCE and DCN.
Reviewed-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
dcn20_validate_bandwidth_fp() is invoked while FPU access has been
enabled. FPU access requires disabling preemption even on PREEMPT_RT.
It is not possible to allocate memory with disabled preemption even with
GFP_ATOMIC on PREEMPT_RT.
Move the memory allocation before FPU access is enabled.
To preserve previous "clean" state of "pipes" add a memset() before the
second invocation of dcn20_validate_bandwidth_internal() where the
variable is used.
Acked-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
dcn21_validate_bandwidth_fp() is invoked while FPU access has been
enabled. FPU access requires disabling preemption even on PREEMPT_RT.
It is not possible to allocate memory with disabled preemption even with
GFP_ATOMIC on PREEMPT_RT.
Move the memory allocation before FPU access is enabled.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217928
Acked-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Add a warning if the FPU is used from any context other than task
context. This is only precaution since the code is not able to be used
from softirq while the API allows it on x86 for instance.
Acked-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
The fpu_recursion_depth counter is used to ensure that dc_fpu_begin()
can be invoked multiple times while the FPU-disable function itself is
only invoked once. Also the counter part (dc_fpu_end()) is ballanced
properly.
Instead of using the get_cpu_ptr() dance around the inc it is simpler to
increment the per-CPU variable directly. Also the per-CPU variable has
to be incremented and decremented on the same CPU. This is ensured by
the inner-part which disables preemption. This is kind of not obvious,
works and the preempt-counter is touched a few times for no reason.
Disable preemption before incrementing fpu_recursion_depth for the first
time. Keep preemption disabled until dc_fpu_end() where the counter is
decremented making it obvious that the preemption has to stay disabled
while the counter is non-zero.
Use simple inc/dec functions.
Remove the nested preempt_disable/enable functions which are now not
needed.
Acked-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This is a revert of the commit mentioned below while it is not wrong, as
in the kernel will explode, having migrate_disable() here it is
complete waste of resources.
Additionally commit message is plain wrong the review tag does not make
it any better. The migrate_disable() interface has a fat comment
describing it and it includes the word "undesired" in the headline which
should tickle people to read it before using it.
Initially I assumed it is worded too harsh but now I beg to differ.
The reviewer of the original commit, even not understanding what
migrate_disable() does should ask the following:
- migrate_disable() is added only to the CONFIG_X86 block and it claims
to protect fpu_recursion_depth. Why are the other the architectures
excluded?
- migrate_disable() is added after fpu_recursion_depth was modified.
Shouldn't it be added before the modification or referencing takes
place?
Moving on.
Disabling preemption DOES prevent CPU migration. A task, that can not be
pushed away from the CPU by the scheduler (due to disabled preemption)
can not be pushed or migrated to another CPU.
Disabling migration DOES NOT ensure consistency of per-CPU variables. It
only ensures that the task acts always on the same per-CPU variable. The
task remains preemptible meaning multiple tasks can access the same
per-CPU variable. This in turn leads to inconsistency for the statement
*pcpu -= 1;
with two tasks on one CPU and a preemption point during the RMW
operation:
Task A Task B
read pcpu to reg # 0
inc reg # 0 -> 1
read pcpu to reg # 0
inc reg # 0 -> 1
write reg to pcpu # 1
write reg to pcpu # 1
At the end pcpu reads 1 but should read 2 instead. Boom.
get_cpu_ptr() already contains a preempt_disable() statement. That means
that the per-CPU variable can only be referenced by a single task which
is currently running. The only inconsistency that can occur if the
variable is additionally accessed from an interrupt.
Remove migrate_disable/enable() from dc_fpu_begin/end().
Cc: Tianci Yin <tianci.yin@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Fixes: 0c316556d1 ("drm/amd/display: Disable migration to ensure consistency of per-CPU variable")
Acked-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why]
Unplug mst hub will cause warning. That's because
dm_helpers_construct_old_payload() is changed to be called after
payload removement from dc link.
In dm_helpers_construct_old_payload(), We refer to the vcpi in
payload allocation table of dc link to construct the old payload
and payload is no longer in the table when we call the function
now.
[How]
Refer to the mst_state to construct the number of time slot for old
payload now. Note that dm_helpers_construct_old_payload() is just
a quick workaround before and we are going to abandon it soon.
Fixes: 5aa1dfcdf0 ("drm/mst: Refactor the flow for payload allocation/removement")
Reviewed-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231005080405.169841-1-Wayne.Lin@amd.com
