From: Shawn Guo shawn.guo@linaro.org

The msm/mdp5 driver uses state of drm_private_obj as its global atomic state, which keeps the assignment of hwpipe to plane. With drm_private_obj missing from duplicate state call in context of atomic suspend/resume helpers, mdp5 suspend works with no problem only for the very first time. Any subsequent suspend will hit the following warning, because hwpipe assignment doesn't get duplicated for suspend state.

$ echo mem > /sys/power/state [ 38.111144] PM: suspend entry (deep) [ 38.111185] PM: Syncing filesystems ... done. [ 38.114630] Freezing user space processes ... (elapsed 0.001 seconds) done. [ 38.115912] OOM killer disabled. [ 38.115914] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done. [ 38.122170] ------------[ cut here ]------------ [ 38.122212] WARNING: CPU: 0 PID: 1747 at drivers/gpu/drm/msm/disp/mdp5/mdp5_pipe.c:145 mdp5_pipe_release+0x90/0xc0 [ 38.122215] Modules linked in: [ 38.122222] CPU: 0 PID: 1747 Comm: sh Not tainted 4.19.107-00515-g9d5e4d7a33ed-dirty #323 [ 38.122224] Hardware name: Square, Inc. T2 Devkit (DT) [ 38.122228] pstate: 40000005 (nZcv daif -PAN -UAO) [ 38.122230] pc : mdp5_pipe_release+0x90/0xc0 [ 38.122233] lr : mdp5_pipe_release+0x90/0xc0 [ 38.122235] sp : ffff00000d13b7f0 [ 38.122236] x29: ffff00000d13b7f0 x28: 0000000000000000 [ 38.122240] x27: 0000000000000002 x26: ffff800079adce00 [ 38.122243] x25: ffff800079405200 x24: 0000000000000000 [ 38.122246] x23: ffff80007a78cc08 x22: ffff80007b1cc018 [ 38.122249] x21: ffff80007b1cc000 x20: ffff80007b317080 [ 38.122252] x19: ffff80007a78ce80 x18: 0000000000020000 [ 38.122255] x17: 0000000000000000 x16: 0000000000000000 [ 38.122258] x15: 00000000fffffff0 x14: ffff000008c3fb48 [ 38.122261] x13: ffff000008cdac4a x12: ffff000008c3f000 [ 38.122264] x11: 0000000000000000 x10: ffff000008cda000 [ 38.122267] x9 : 0000000000000000 x8 : ffff000008ce4a40 [ 38.122269] x7 : 0000000000000000 x6 : 0000000039ea41a9 [ 38.122272] x5 : 0000000000000000 x4 : 0000000000000000 [ 38.122275] x3 : ffffffffffffffff x2 : c7580c109cae4500 [ 38.122278] x1 : 0000000000000000 x0 : 0000000000000024 [ 38.122281] Call trace: [ 38.122285] mdp5_pipe_release+0x90/0xc0 [ 38.122288] mdp5_plane_atomic_check+0x2c0/0x448 [ 38.122294] drm_atomic_helper_check_planes+0xd0/0x208 [ 38.122298] drm_atomic_helper_check+0x38/0xa8 [ 38.122302] drm_atomic_check_only+0x3e8/0x630 [ 38.122305] drm_atomic_commit+0x18/0x58 [ 38.122309] __drm_atomic_helper_disable_all.isra.12+0x15c/0x1a8 [ 38.122312] drm_atomic_helper_suspend+0x80/0xf0 [ 38.122316] msm_pm_suspend+0x4c/0x70 [ 38.122320] dpm_run_callback.isra.6+0x20/0x68 [ 38.122323] __device_suspend+0x110/0x308 [ 38.122326] dpm_suspend+0x100/0x1f0 [ 38.122329] dpm_suspend_start+0x64/0x70 [ 38.122334] suspend_devices_and_enter+0x110/0x500 [ 38.122336] pm_suspend+0x268/0x2c0 [ 38.122339] state_store+0x88/0x110 [ 38.122345] kobj_attr_store+0x14/0x28 [ 38.122352] sysfs_kf_write+0x3c/0x50 [ 38.122355] kernfs_fop_write+0x118/0x1e0 [ 38.122360] __vfs_write+0x30/0x168 [ 38.122363] vfs_write+0xa4/0x1a8 [ 38.122366] ksys_write+0x64/0xe8 [ 38.122368] __arm64_sys_write+0x18/0x20 [ 38.122374] el0_svc_common+0x6c/0x178 [ 38.122377] el0_svc_compat_handler+0x1c/0x28 [ 38.122381] el0_svc_compat+0x8/0x18 [ 38.122383] ---[ end trace 24145b7d8545345b ]--- [ 38.491552] Disabling non-boot CPUs ...

Let's add a flag for duplicating the state of drm_private_obj and set the flag from msm/mdp5 driver, so that the problem can be fixed while other drivers using drm_private_obj stay unaffected.

Signed-off-by: Shawn Guo shawn.guo@linaro.org --- Changes for v2: - Add a flag to duplicate the state of drm_private_obj conditionally, so that other drivers using drm_private_obj stay unaffected.

drivers/gpu/drm/drm_atomic_helper.c | 22 ++++++++++++++++++++++ drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c | 7 +++++++ include/drm/drm_atomic.h | 11 +++++++++++ 3 files changed, 40 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 85d163f16801..4bf041730b9e 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -3140,6 +3140,7 @@ drm_atomic_helper_duplicate_state(struct drm_device *dev, struct drm_atomic_state *state; struct drm_connector *conn; struct drm_connector_list_iter conn_iter; + struct drm_private_obj *priv_obj; struct drm_plane *plane; struct drm_crtc *crtc; int err = 0; @@ -3184,6 +3185,19 @@ drm_atomic_helper_duplicate_state(struct drm_device *dev, } drm_connector_list_iter_end(&conn_iter);

+ drm_for_each_privobj(priv_obj, dev) { + struct drm_private_state *priv_state; + + if (!priv_obj->needs_duplicate_state) + continue; + + priv_state = drm_atomic_get_private_obj_state(state, priv_obj); + if (IS_ERR(priv_state)) { + err = PTR_ERR(priv_state); + goto free; + } + } + /* clear the acquire context so that it isn't accidentally reused */ state->acquire_ctx = NULL;

@@ -3278,6 +3292,8 @@ int drm_atomic_helper_commit_duplicated_state(struct drm_atomic_state *state, struct drm_connector_state *new_conn_state; struct drm_crtc *crtc; struct drm_crtc_state *new_crtc_state; + struct drm_private_state *new_priv_state; + struct drm_private_obj *priv_obj;

state->acquire_ctx = ctx;

@@ -3290,6 +3306,12 @@ int drm_atomic_helper_commit_duplicated_state(struct drm_atomic_state *state, for_each_new_connector_in_state(state, connector, new_conn_state, i) state->connectors[i].old_state = connector->state;

+ for_each_new_private_obj_in_state(state, priv_obj, new_priv_state, i) { + if (!priv_obj->needs_duplicate_state) + continue; + state->private_objs[i].old_state = priv_obj->state; + } + ret = drm_atomic_commit(state);

state->acquire_ctx = NULL; diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c index 19ec48695ffb..20971c75f3a2 100644 --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c @@ -139,6 +139,13 @@ static int mdp5_global_obj_init(struct mdp5_kms *mdp5_kms) drm_atomic_private_obj_init(mdp5_kms->dev, &mdp5_kms->glob_state, &state->base, &mdp5_global_state_funcs); + + /* + * Set needs_duplicate_state flag, as we have assignment of hwpipe in + * global atomic state that needs to be duplicated for suspend state. + */ + mdp5_kms->glob_state.needs_duplicate_state = true; + return 0; }

diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h index 7b6cb4774e7d..72d35ca7b59e 100644 --- a/include/drm/drm_atomic.h +++ b/include/drm/drm_atomic.h @@ -273,6 +273,17 @@ struct drm_private_obj { * &drm_private_state_funcs. */ const struct drm_private_state_funcs *funcs; + + /** + * @needs_duplicate_state: + * + * A flag that's set by driver in order to duplicate the state of this + * private object in drm_atomic_helper_duplicate_state(). It's required + * by drivers like msm/mdp5 where the state is used as the driver global + * atomic state, and needs to be duplicated in context of suspend helper + * drm_atomic_helper_suspend(), restored on drm_atomic_helper_resume(). + */ + bool needs_duplicate_state; };

/**