On 5/30/2018 8:51 PM, Deucher, Alexander wrote: >> -----Original Message----- >> From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On Behalf >> Of Shirish S >> Sent: Wednesday, May 30, 2018 6:20 AM >> To: amd-gfx at lists.freedesktop.org; Wentland, Harry >> <Harry.Wentland at amd.com>; Zhu, Rex <Rex.Zhu at amd.com> >> Cc: S, Shirish <Shirish.S at amd.com> >> Subject: [PATCH] drm/amdgpu: replace mutex with spin_lock >> >> mutex's lead to sleeps which should be avoided in atomic context. >> Hence this patch replaces it with the spin_locks. >> >> Signed-off-by: Shirish S <shirish.s at amd.com> > Does this actually fix a bug or is it just to be safe? Do actually call atom command tables in an atomic context? I have re-spun V2 patch, with the stack trace so that you can see the path taken. For reference below is the trace: BUG: sleeping function called from invalid context at kernel/locking/mutex.c:238 in_atomic(): 1, irqs_disabled(): 1, pid: 89, name: kworker/u4:3 CPU: 1 PID: 89 Comm: kworker/u4:3 Tainted: G       W 4.14.43 #8 Workqueue: events_unbound commit_work Call Trace:  dump_stack+0x4d/0x63  ___might_sleep+0x11f/0x12e  mutex_lock+0x20/0x42  amdgpu_atom_execute_table+0x26/0x72  enable_disp_power_gating_v2_1+0x85/0xae  dce110_enable_display_power_gating+0x83/0x1b1  dce110_power_down_fe+0x4a/0x6d  dc_post_update_surfaces_to_stream+0x59/0x87  amdgpu_dm_do_flip+0x239/0x298  amdgpu_dm_commit_planes.isra.23+0x379/0x54b  ? drm_calc_timestamping_constants+0x14b/0x15c  amdgpu_dm_atomic_commit_tail+0x4fc/0x5d2  ? wait_for_common+0x5b/0x69  commit_tail+0x42/0x64  process_one_work+0x1b0/0x314  worker_thread+0x1cb/0x2c1  ? create_worker+0x1da/0x1da  kthread+0x156/0x15e  ? kthread_flush_work+0xea/0xea  ret_from_fork+0x22/0x40 Its caused when a BUG hit in the kernel. Thanks & Regards, Shirish S > Alex > >> --- >> drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c | 2 +- >> drivers/gpu/drm/amd/amdgpu/atom.c | 4 ++-- >> drivers/gpu/drm/amd/amdgpu/atom.h | 3 ++- >> 3 files changed, 5 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c >> b/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c >> index bf872f6..ba3d4b9 100644 >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c >> @@ -2033,7 +2033,7 @@ int amdgpu_atombios_init(struct amdgpu_device >> *adev) >> return -ENOMEM; >> } >> >> - mutex_init(&adev->mode_info.atom_context->mutex); >> + spin_lock_init(&adev->mode_info.atom_context->lock); >> if (adev->is_atom_fw) { >> amdgpu_atomfirmware_scratch_regs_init(adev); >> amdgpu_atomfirmware_allocate_fb_scratch(adev); >> diff --git a/drivers/gpu/drm/amd/amdgpu/atom.c >> b/drivers/gpu/drm/amd/amdgpu/atom.c >> index 69500a8..bfd98f0 100644 >> --- a/drivers/gpu/drm/amd/amdgpu/atom.c >> +++ b/drivers/gpu/drm/amd/amdgpu/atom.c >> @@ -1261,7 +1261,7 @@ int amdgpu_atom_execute_table(struct >> atom_context *ctx, int index, uint32_t * pa { >> int r; >> >> - mutex_lock(&ctx->mutex); >> + spin_lock(&ctx->lock); >> /* reset data block */ >> ctx->data_block = 0; >> /* reset reg block */ >> @@ -1274,7 +1274,7 @@ int amdgpu_atom_execute_table(struct >> atom_context *ctx, int index, uint32_t * pa >> ctx->divmul[0] = 0; >> ctx->divmul[1] = 0; >> r = amdgpu_atom_execute_table_locked(ctx, index, params); >> - mutex_unlock(&ctx->mutex); >> + spin_unlock(&ctx->lock); >> return r; >> } >> >> diff --git a/drivers/gpu/drm/amd/amdgpu/atom.h >> b/drivers/gpu/drm/amd/amdgpu/atom.h >> index a391709..cdfb0d0 100644 >> --- a/drivers/gpu/drm/amd/amdgpu/atom.h >> +++ b/drivers/gpu/drm/amd/amdgpu/atom.h >> @@ -26,6 +26,7 @@ >> #define ATOM_H >> >> #include <linux/types.h> >> +#include <linux/spinlock_types.h> >> #include <drm/drmP.h> >> >> #define ATOM_BIOS_MAGIC 0xAA55 >> @@ -125,7 +126,7 @@ struct card_info { >> >> struct atom_context { >> struct card_info *card; >> - struct mutex mutex; >> + spinlock_t lock; >> void *bios; >> uint32_t cmd_table, data_table; >> uint16_t *iio; >> -- >> 2.7.4 >> >> _______________________________________________ >> amd-gfx mailing list >> amd-gfx at lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/amd-gfx -- Regards, Shirish S -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://lists.freedesktop.org/archives/amd-gfx/attachments/20180531/4fefe6ef/attachment.html>
