From: Abhinav Kumar quic_abhinavk@quicinc.com
[ Upstream commit 9a0cdcd6649b76f0b7ceec0e55b0a718321e34d3 ]
adv7533 bridge tries to dynamically switch lanes based on the mode by detaching and attaching the mipi dsi device.
This approach is incorrect because this method of dynamic switch of detaching and attaching the mipi dsi device also results in removing and adding the component which is not necessary.
This approach is also prone to deadlocks. So for example, on the db410c whenever this path is executed with lockdep enabled, this results in a deadlock due to below ordering of locks.
-> #1 (crtc_ww_class_acquire){+.+.}-{0:0}: lock_acquire+0x6c/0x90 drm_modeset_acquire_init+0xf4/0x150 drmm_mode_config_init+0x220/0x770 msm_drm_bind+0x13c/0x654 try_to_bring_up_aggregate_device+0x164/0x1d0 __component_add+0xa8/0x174 component_add+0x18/0x2c dsi_dev_attach+0x24/0x30 dsi_host_attach+0x98/0x14c devm_mipi_dsi_attach+0x38/0xb0 adv7533_attach_dsi+0x8c/0x110 adv7511_probe+0x5a0/0x930 i2c_device_probe+0x30c/0x350 really_probe.part.0+0x9c/0x2b0 __driver_probe_device+0x98/0x144 driver_probe_device+0xac/0x14c __device_attach_driver+0xbc/0x124 bus_for_each_drv+0x78/0xd0 __device_attach+0xa8/0x1c0 device_initial_probe+0x18/0x24 bus_probe_device+0xa0/0xac deferred_probe_work_func+0x90/0xd0 process_one_work+0x28c/0x6b0 worker_thread+0x240/0x444 kthread+0x110/0x114 ret_from_fork+0x10/0x20
-> #0 (component_mutex){+.+.}-{3:3}: __lock_acquire+0x1280/0x20ac lock_acquire.part.0+0xe0/0x230 lock_acquire+0x6c/0x90 __mutex_lock+0x84/0x400 mutex_lock_nested+0x3c/0x70 component_del+0x34/0x170 dsi_dev_detach+0x24/0x30 dsi_host_detach+0x20/0x64 mipi_dsi_detach+0x2c/0x40 adv7533_mode_set+0x64/0x90 adv7511_bridge_mode_set+0x210/0x214 drm_bridge_chain_mode_set+0x5c/0x84 crtc_set_mode+0x18c/0x1dc drm_atomic_helper_commit_modeset_disables+0x40/0x50 msm_atomic_commit_tail+0x1d0/0x6e0 commit_tail+0xa4/0x180 drm_atomic_helper_commit+0x178/0x3b0 drm_atomic_commit+0xa4/0xe0 drm_client_modeset_commit_atomic+0x228/0x284 drm_client_modeset_commit_locked+0x64/0x1d0 drm_client_modeset_commit+0x34/0x60 drm_fb_helper_lastclose+0x74/0xcc drm_lastclose+0x3c/0x80 drm_release+0xfc/0x114 __fput+0x70/0x224 ____fput+0x14/0x20 task_work_run+0x88/0x1a0 do_exit+0x350/0xa50 do_group_exit+0x38/0xa4 __wake_up_parent+0x0/0x34 invoke_syscall+0x48/0x114 el0_svc_common.constprop.0+0x60/0x11c do_el0_svc+0x30/0xc0 el0_svc+0x58/0x100 el0t_64_sync_handler+0x1b0/0x1bc el0t_64_sync+0x18c/0x190
Due to above reasons, remove the dynamic lane switching code from adv7533 bridge chip and filter out the modes which would need different number of lanes as compared to the initialization time using the mode_valid callback.
This can be potentially re-introduced by using the pre_enable() callback but this needs to be evaluated first whether such an approach will work so this will be done with a separate change.
changes since RFC: - Fix commit text and add TODO comment
changes in v2: - Fix checkpatch formatting errors
Fixes: 62b2f026cd8e ("drm/bridge: adv7533: Change number of DSI lanes dynamically") Closes: https://gitlab.freedesktop.org/drm/msm/-/issues/16 Suggested-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Signed-off-by: Abhinav Kumar quic_abhinavk@quicinc.com Reviewed-by: Robert Foss robert.foss@linaro.org Link: https://lore.kernel.org/r/1661797363-7564-1-git-send-email-quic_abhinavk@qui... Signed-off-by: Robert Foss robert.foss@linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/1665522649-3423-1-git-send-ema... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/bridge/adv7511/adv7511.h | 3 ++- drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 18 ++++++++++---- drivers/gpu/drm/bridge/adv7511/adv7533.c | 25 ++++++++++---------- 3 files changed, 29 insertions(+), 17 deletions(-)
diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511.h b/drivers/gpu/drm/bridge/adv7511/adv7511.h index aeeb09a27202..fdd8e3d3232e 100644 --- a/drivers/gpu/drm/bridge/adv7511/adv7511.h +++ b/drivers/gpu/drm/bridge/adv7511/adv7511.h @@ -395,7 +395,8 @@ static inline int adv7511_cec_init(struct device *dev, struct adv7511 *adv7511)
void adv7533_dsi_power_on(struct adv7511 *adv); void adv7533_dsi_power_off(struct adv7511 *adv); -void adv7533_mode_set(struct adv7511 *adv, const struct drm_display_mode *mode); +enum drm_mode_status adv7533_mode_valid(struct adv7511 *adv, + const struct drm_display_mode *mode); int adv7533_patch_registers(struct adv7511 *adv); int adv7533_patch_cec_registers(struct adv7511 *adv); int adv7533_attach_dsi(struct adv7511 *adv); diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c index 3dc551d223d6..44762116aac9 100644 --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c @@ -697,7 +697,7 @@ adv7511_detect(struct adv7511 *adv7511, struct drm_connector *connector) }
static enum drm_mode_status adv7511_mode_valid(struct adv7511 *adv7511, - struct drm_display_mode *mode) + const struct drm_display_mode *mode) { if (mode->clock > 165000) return MODE_CLOCK_HIGH; @@ -791,9 +791,6 @@ static void adv7511_mode_set(struct adv7511 *adv7511, regmap_update_bits(adv7511->regmap, 0x17, 0x60, (vsync_polarity << 6) | (hsync_polarity << 5));
- if (adv7511->type == ADV7533 || adv7511->type == ADV7535) - adv7533_mode_set(adv7511, adj_mode); - drm_mode_copy(&adv7511->curr_mode, adj_mode);
/* @@ -913,6 +910,18 @@ static void adv7511_bridge_mode_set(struct drm_bridge *bridge, adv7511_mode_set(adv, mode, adj_mode); }
+static enum drm_mode_status adv7511_bridge_mode_valid(struct drm_bridge *bridge, + const struct drm_display_info *info, + const struct drm_display_mode *mode) +{ + struct adv7511 *adv = bridge_to_adv7511(bridge); + + if (adv->type == ADV7533 || adv->type == ADV7535) + return adv7533_mode_valid(adv, mode); + else + return adv7511_mode_valid(adv, mode); +} + static int adv7511_bridge_attach(struct drm_bridge *bridge, enum drm_bridge_attach_flags flags) { @@ -963,6 +972,7 @@ static const struct drm_bridge_funcs adv7511_bridge_funcs = { .enable = adv7511_bridge_enable, .disable = adv7511_bridge_disable, .mode_set = adv7511_bridge_mode_set, + .mode_valid = adv7511_bridge_mode_valid, .attach = adv7511_bridge_attach, .detect = adv7511_bridge_detect, .get_edid = adv7511_bridge_get_edid, diff --git a/drivers/gpu/drm/bridge/adv7511/adv7533.c b/drivers/gpu/drm/bridge/adv7511/adv7533.c index 59d718bde8c4..7eda12f338a1 100644 --- a/drivers/gpu/drm/bridge/adv7511/adv7533.c +++ b/drivers/gpu/drm/bridge/adv7511/adv7533.c @@ -100,26 +100,27 @@ void adv7533_dsi_power_off(struct adv7511 *adv) regmap_write(adv->regmap_cec, 0x27, 0x0b); }
-void adv7533_mode_set(struct adv7511 *adv, const struct drm_display_mode *mode) +enum drm_mode_status adv7533_mode_valid(struct adv7511 *adv, + const struct drm_display_mode *mode) { + int lanes; struct mipi_dsi_device *dsi = adv->dsi; - int lanes, ret; - - if (adv->num_dsi_lanes != 4) - return;
if (mode->clock > 80000) lanes = 4; else lanes = 3;
- if (lanes != dsi->lanes) { - mipi_dsi_detach(dsi); - dsi->lanes = lanes; - ret = mipi_dsi_attach(dsi); - if (ret) - dev_err(&dsi->dev, "failed to change host lanes\n"); - } + /* + * TODO: add support for dynamic switching of lanes + * by using the bridge pre_enable() op . Till then filter + * out the modes which shall need different number of lanes + * than what was configured in the device tree. + */ + if (lanes != dsi->lanes) + return MODE_BAD; + + return MODE_OK; }
int adv7533_patch_registers(struct adv7511 *adv)