This is a note to let you know that I've just added the patch titled
drm/amd/display: Fix nested FPU context in dcn21_validate_bandwidth()
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-amd-display-fix-nested-fpu-context-in-dcn21_validate_bandwidth.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 15e8b95d5f7509e0b09289be8c422c459c9f0412 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Holger=20Hoffst=C3=A4tte?= <holger@xxxxxxxxxxxxxxxxxxxxxx>
Date: Fri, 5 Mar 2021 12:39:21 +0100
Subject: drm/amd/display: Fix nested FPU context in dcn21_validate_bandwidth()
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From: Holger Hoffstätte <holger@xxxxxxxxxxxxxxxxxxxxxx>
commit 15e8b95d5f7509e0b09289be8c422c459c9f0412 upstream.
Commit 41401ac67791 added FPU wrappers to dcn21_validate_bandwidth(),
which was correct. Unfortunately a nested function alredy contained
DC_FP_START()/DC_FP_END() calls, which results in nested FPU context
enter/exit and complaints by kernel_fpu_begin_mask().
This can be observed e.g. with 5.10.20, which backported 41401ac67791
and now emits the following warning on boot:
WARNING: CPU: 6 PID: 858 at arch/x86/kernel/fpu/core.c:129 kernel_fpu_begin_mask+0xa5/0xc0
Call Trace:
dcn21_calculate_wm+0x47/0xa90 [amdgpu]
dcn21_validate_bandwidth_fp+0x15d/0x2b0 [amdgpu]
dcn21_validate_bandwidth+0x29/0x40 [amdgpu]
dc_validate_global_state+0x3c7/0x4c0 [amdgpu]
The warning is emitted due to the additional DC_FP_START/END calls in
patch_bounding_box(), which is inlined into dcn21_calculate_wm(),
its only caller. Removing the calls brings the code in line with
dcn20 and makes the warning disappear.
Fixes: 41401ac67791 ("drm/amd/display: Add FPU wrappers to dcn21_validate_bandwidth()")
Signed-off-by: Holger Hoffstätte <holger@xxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/amd/display/dc/dcn21/dcn21_resource.c | 4 ----
1 file changed, 4 deletions(-)
--- a/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_resource.c
@@ -1058,8 +1058,6 @@ static void patch_bounding_box(struct dc
{
int i;
- DC_FP_START();
-
if (dc->bb_overrides.sr_exit_time_ns) {
for (i = 0; i < WM_SET_COUNT; i++) {
dc->clk_mgr->bw_params->wm_table.entries[i].sr_exit_time_us =
@@ -1084,8 +1082,6 @@ static void patch_bounding_box(struct dc
dc->bb_overrides.dram_clock_change_latency_ns / 1000.0;
}
}
-
- DC_FP_END();
}
void dcn21_calculate_wm(
Patches currently in stable-queue which might be from holger@xxxxxxxxxxxxxxxxxxxxxx are
queue-5.10/drm-amd-display-fix-nested-fpu-context-in-dcn21_validate_bandwidth.patch
queue-5.10/drm-amdgpu-display-use-gfp_atomic-in-dcn21_validate_bandwidth_fp.patch
