From 27d3313807296c3943a96ceef8c2b7279cb56962 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 18 May 2024 19:39:59 +0200 Subject: Adding debian version 6.7.7-1. Signed-off-by: Daniel Baumann --- ...play-Remove-migrate_en-dis-from-dc_fpu_be.patch | 86 ---------------------- 1 file changed, 86 deletions(-) delete mode 100644 debian/patches-rt/0001-drm-amd-display-Remove-migrate_en-dis-from-dc_fpu_be.patch (limited to 'debian/patches-rt/0001-drm-amd-display-Remove-migrate_en-dis-from-dc_fpu_be.patch') diff --git a/debian/patches-rt/0001-drm-amd-display-Remove-migrate_en-dis-from-dc_fpu_be.patch b/debian/patches-rt/0001-drm-amd-display-Remove-migrate_en-dis-from-dc_fpu_be.patch deleted file mode 100644 index b78f988da5..0000000000 --- a/debian/patches-rt/0001-drm-amd-display-Remove-migrate_en-dis-from-dc_fpu_be.patch +++ /dev/null @@ -1,86 +0,0 @@ -From: Sebastian Andrzej Siewior -Date: Thu, 21 Sep 2023 16:15:12 +0200 -Subject: [PATCH 1/5] drm/amd/display: Remove migrate_en/dis from - dc_fpu_begin(). -Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz - -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 -Cc: Aurabindo Pillai -Fixes: 0c316556d1249 ("drm/amd/display: Disable migration to ensure consistency of per-CPU variable") -Link: https://lore.kernel.org/r/20230921141516.520471-2-bigeasy@linutronix.de -Signed-off-by: Sebastian Andrzej Siewior ---- - drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c | 2 -- - 1 file changed, 2 deletions(-) - ---- a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c -+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c -@@ -91,7 +91,6 @@ void dc_fpu_begin(const char *function_n - - if (*pcpu == 1) { - #if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH) -- migrate_disable(); - kernel_fpu_begin(); - #elif defined(CONFIG_PPC64) - if (cpu_has_feature(CPU_FTR_VSX_COMP)) { -@@ -132,7 +131,6 @@ void dc_fpu_end(const char *function_nam - if (*pcpu <= 0) { - #if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH) - kernel_fpu_end(); -- migrate_enable(); - #elif defined(CONFIG_PPC64) - if (cpu_has_feature(CPU_FTR_VSX_COMP)) { - disable_kernel_vsx(); -- cgit v1.2.3