| From 3f65b1e2f424f44585bd701024a3bfd0b1e0ade2 Mon Sep 17 00:00:00 2001 |
| From: Kuogee Hsieh <quic_khsieh@quicinc.com> |
| Date: Tue, 26 Apr 2022 14:12:14 -0700 |
| Subject: drm/msm/dp: remove fail safe mode related code |
| |
| From: Kuogee Hsieh <quic_khsieh@quicinc.com> |
| |
| commit 3f65b1e2f424f44585bd701024a3bfd0b1e0ade2 upstream. |
| |
| Current DP driver implementation has adding safe mode done at |
| dp_hpd_plug_handle() which is expected to be executed under event |
| thread context. |
| |
| However there is possible circular locking happen (see blow stack trace) |
| after edp driver call dp_hpd_plug_handle() from dp_bridge_enable() which |
| is executed under drm_thread context. |
| |
| After review all possibilities methods and as discussed on |
| https://patchwork.freedesktop.org/patch/483155/, supporting EDID |
| compliance tests in the driver is quite hacky. As seen with other |
| vendor drivers, supporting these will be much easier with IGT. Hence |
| removing all the related fail safe code for it so that no possibility |
| of circular lock will happen. |
| Reviewed-by: Stephen Boyd <swboyd@chromium.org> |
| Reviewed-by: Douglas Anderson <dianders@chromium.org> |
| Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> |
| |
| ====================================================== |
| WARNING: possible circular locking dependency detected |
| 5.15.35-lockdep #6 Tainted: G W |
| ------------------------------------------------------ |
| frecon/429 is trying to acquire lock: |
| ffffff808dc3c4e8 (&dev->mode_config.mutex){+.+.}-{3:3}, at: |
| dp_panel_add_fail_safe_mode+0x4c/0xa0 |
| |
| but task is already holding lock: |
| ffffff808dc441e0 (&kms->commit_lock[i]){+.+.}-{3:3}, at: lock_crtcs+0xb4/0x124 |
| |
| which lock already depends on the new lock. |
| |
| the existing dependency chain (in reverse order) is: |
| |
| -> #3 (&kms->commit_lock[i]){+.+.}-{3:3}: |
| __mutex_lock_common+0x174/0x1a64 |
| mutex_lock_nested+0x98/0xac |
| lock_crtcs+0xb4/0x124 |
| msm_atomic_commit_tail+0x330/0x748 |
| commit_tail+0x19c/0x278 |
| drm_atomic_helper_commit+0x1dc/0x1f0 |
| drm_atomic_commit+0xc0/0xd8 |
| drm_atomic_helper_set_config+0xb4/0x134 |
| drm_mode_setcrtc+0x688/0x1248 |
| drm_ioctl_kernel+0x1e4/0x338 |
| drm_ioctl+0x3a4/0x684 |
| __arm64_sys_ioctl+0x118/0x154 |
| invoke_syscall+0x78/0x224 |
| el0_svc_common+0x178/0x200 |
| do_el0_svc+0x94/0x13c |
| el0_svc+0x5c/0xec |
| el0t_64_sync_handler+0x78/0x108 |
| el0t_64_sync+0x1a4/0x1a8 |
| |
| -> #2 (crtc_ww_class_mutex){+.+.}-{3:3}: |
| __mutex_lock_common+0x174/0x1a64 |
| ww_mutex_lock+0xb8/0x278 |
| modeset_lock+0x304/0x4ac |
| drm_modeset_lock+0x4c/0x7c |
| drmm_mode_config_init+0x4a8/0xc50 |
| msm_drm_init+0x274/0xac0 |
| msm_drm_bind+0x20/0x2c |
| try_to_bring_up_master+0x3dc/0x470 |
| __component_add+0x18c/0x3c0 |
| component_add+0x1c/0x28 |
| dp_display_probe+0x954/0xa98 |
| platform_probe+0x124/0x15c |
| really_probe+0x1b0/0x5f8 |
| __driver_probe_device+0x174/0x20c |
| driver_probe_device+0x70/0x134 |
| __device_attach_driver+0x130/0x1d0 |
| bus_for_each_drv+0xfc/0x14c |
| __device_attach+0x1bc/0x2bc |
| device_initial_probe+0x1c/0x28 |
| bus_probe_device+0x94/0x178 |
| deferred_probe_work_func+0x1a4/0x1f0 |
| process_one_work+0x5d4/0x9dc |
| worker_thread+0x898/0xccc |
| kthread+0x2d4/0x3d4 |
| ret_from_fork+0x10/0x20 |
| |
| -> #1 (crtc_ww_class_acquire){+.+.}-{0:0}: |
| ww_acquire_init+0x1c4/0x2c8 |
| drm_modeset_acquire_init+0x44/0xc8 |
| drm_helper_probe_single_connector_modes+0xb0/0x12dc |
| drm_mode_getconnector+0x5dc/0xfe8 |
| drm_ioctl_kernel+0x1e4/0x338 |
| drm_ioctl+0x3a4/0x684 |
| __arm64_sys_ioctl+0x118/0x154 |
| invoke_syscall+0x78/0x224 |
| el0_svc_common+0x178/0x200 |
| do_el0_svc+0x94/0x13c |
| el0_svc+0x5c/0xec |
| el0t_64_sync_handler+0x78/0x108 |
| el0t_64_sync+0x1a4/0x1a8 |
| |
| -> #0 (&dev->mode_config.mutex){+.+.}-{3:3}: |
| __lock_acquire+0x2650/0x672c |
| lock_acquire+0x1b4/0x4ac |
| __mutex_lock_common+0x174/0x1a64 |
| mutex_lock_nested+0x98/0xac |
| dp_panel_add_fail_safe_mode+0x4c/0xa0 |
| dp_hpd_plug_handle+0x1f0/0x280 |
| dp_bridge_enable+0x94/0x2b8 |
| drm_atomic_bridge_chain_enable+0x11c/0x168 |
| drm_atomic_helper_commit_modeset_enables+0x500/0x740 |
| msm_atomic_commit_tail+0x3e4/0x748 |
| commit_tail+0x19c/0x278 |
| drm_atomic_helper_commit+0x1dc/0x1f0 |
| drm_atomic_commit+0xc0/0xd8 |
| drm_atomic_helper_set_config+0xb4/0x134 |
| drm_mode_setcrtc+0x688/0x1248 |
| drm_ioctl_kernel+0x1e4/0x338 |
| drm_ioctl+0x3a4/0x684 |
| __arm64_sys_ioctl+0x118/0x154 |
| invoke_syscall+0x78/0x224 |
| el0_svc_common+0x178/0x200 |
| do_el0_svc+0x94/0x13c |
| el0_svc+0x5c/0xec |
| el0t_64_sync_handler+0x78/0x108 |
| el0t_64_sync+0x1a4/0x1a8 |
| |
| Changes in v2: |
| -- re text commit title |
| -- remove all fail safe mode |
| |
| Changes in v3: |
| -- remove dp_panel_add_fail_safe_mode() from dp_panel.h |
| -- add Fixes |
| |
| Changes in v5: |
| -- to=dianders@chromium.org |
| |
| Changes in v6: |
| -- fix Fixes commit ID |
| |
| Fixes: 8b2c181e3dcf ("drm/msm/dp: add fail safe mode outside of event_mutex context") |
| Reported-by: Douglas Anderson <dianders@chromium.org> |
| Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com> |
| Link: https://lore.kernel.org/r/1651007534-31842-1-git-send-email-quic_khsieh@quicinc.com |
| Signed-off-by: Rob Clark <robdclark@chromium.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/gpu/drm/msm/dp/dp_display.c | 6 ------ |
| drivers/gpu/drm/msm/dp/dp_panel.c | 11 ----------- |
| drivers/gpu/drm/msm/dp/dp_panel.h | 1 - |
| 3 files changed, 18 deletions(-) |
| |
| --- a/drivers/gpu/drm/msm/dp/dp_display.c |
| +++ b/drivers/gpu/drm/msm/dp/dp_display.c |
| @@ -551,12 +551,6 @@ static int dp_hpd_plug_handle(struct dp_ |
| |
| mutex_unlock(&dp->event_mutex); |
| |
| - /* |
| - * add fail safe mode outside event_mutex scope |
| - * to avoid potiential circular lock with drm thread |
| - */ |
| - dp_panel_add_fail_safe_mode(dp->dp_display.connector); |
| - |
| /* uevent will complete connection part */ |
| return 0; |
| }; |
| --- a/drivers/gpu/drm/msm/dp/dp_panel.c |
| +++ b/drivers/gpu/drm/msm/dp/dp_panel.c |
| @@ -151,15 +151,6 @@ static int dp_panel_update_modes(struct |
| return rc; |
| } |
| |
| -void dp_panel_add_fail_safe_mode(struct drm_connector *connector) |
| -{ |
| - /* fail safe edid */ |
| - mutex_lock(&connector->dev->mode_config.mutex); |
| - if (drm_add_modes_noedid(connector, 640, 480)) |
| - drm_set_preferred_mode(connector, 640, 480); |
| - mutex_unlock(&connector->dev->mode_config.mutex); |
| -} |
| - |
| int dp_panel_read_sink_caps(struct dp_panel *dp_panel, |
| struct drm_connector *connector) |
| { |
| @@ -215,8 +206,6 @@ int dp_panel_read_sink_caps(struct dp_pa |
| rc = -ETIMEDOUT; |
| goto end; |
| } |
| - |
| - dp_panel_add_fail_safe_mode(connector); |
| } |
| |
| if (panel->aux_cfg_update_done) { |
| --- a/drivers/gpu/drm/msm/dp/dp_panel.h |
| +++ b/drivers/gpu/drm/msm/dp/dp_panel.h |
| @@ -59,7 +59,6 @@ int dp_panel_init_panel_info(struct dp_p |
| int dp_panel_deinit(struct dp_panel *dp_panel); |
| int dp_panel_timing_cfg(struct dp_panel *dp_panel); |
| void dp_panel_dump_regs(struct dp_panel *dp_panel); |
| -void dp_panel_add_fail_safe_mode(struct drm_connector *connector); |
| int dp_panel_read_sink_caps(struct dp_panel *dp_panel, |
| struct drm_connector *connector); |
| u32 dp_panel_get_mode_bpp(struct dp_panel *dp_panel, u32 mode_max_bpp, |
