[Freedreno] [PATCH] drm/bridge: adv7533: remove dynamic lane switching from adv7533 bridge
Abhinav Kumar
quic_abhinavk at quicinc.com
Thu Oct 6 15:07:11 UTC 2022
Hi Robert
Thanks for the review.
On 10/4/2022 8:55 AM, Robert Foss wrote:
> On Mon, 29 Aug 2022 at 20:23, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
>>
>> 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
>>
>> 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 at linaro.org>
>> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
>> ---
>> 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 9e3bb8a8ee40..0a7cec80b75d 100644
>> --- a/drivers/gpu/drm/bridge/adv7511/adv7511.h
>> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511.h
>> @@ -417,7 +417,8 @@ 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 5bb9300040dd..1115ef9be83c 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)
>> {
>> @@ -960,6 +969,7 @@ 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 ef6270806d1d..5f590abd6403 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)
>> --
>> 2.7.4
>>
>
> This patch has some checkpatch --style warnings, with those fixed feel
> free to add my r-b.
I checked just now. I dont see any checkpatch errors on my end.
I am not sure if we are running different versions of checkpatch but I
am using the one at the tip of msm-next.
https://gitlab.freedesktop.org/drm/msm/-/blob/msm-next/scripts/checkpatch.pl
>
> Reviewed-by: Robert Foss <robert.foss at linaro.org>
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