Re: [Intel-gfx] [PATCH v2] drm/probe_helper: sort out poll_running vs poll_enabled

2023-01-24 Thread Dmitry Baryshkov

On 24/01/2023 10:55, Jani Nikula wrote:

On Wed, 18 Jan 2023, Dmitry Baryshkov  wrote:

There are two flags attemting to guard connector polling:
poll_enabled and poll_running. While poll_enabled semantics is clearly
defined and fully adhered (mark that drm_kms_helper_poll_init() was
called and not finalized by the _fini() call), the poll_running flag
doesn't have such clearliness.

This flag is used only in drm_helper_probe_single_connector_modes() to
guard calling of drm_kms_helper_poll_enable, it doesn't guard the
drm_kms_helper_poll_fini(), etc. Change it to only be set if the polling
is actually running. Tie HPD enablement to this flag.

This fixes the following warning reported after merging the HPD series:

Hot plug detection already enabled
WARNING: CPU: 2 PID: 9 at drivers/gpu/drm/drm_bridge.c:1257 
drm_bridge_hpd_enable+0x94/0x9c [drm]
Modules linked in: videobuf2_memops snd_soc_simple_card 
snd_soc_simple_card_utils fsl_imx8_ddr_perf videobuf2_common snd_soc_imx_spdif 
adv7511 etnaviv imx8m_ddrc imx_dcss mc cec nwl_dsi gov
CPU: 2 PID: 9 Comm: kworker/u8:0 Not tainted 6.2.0-rc2-15208-g25b283acd578 #6
Hardware name: NXP i.MX8MQ EVK (DT)
Workqueue: events_unbound deferred_probe_work_func
pstate: 6005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : drm_bridge_hpd_enable+0x94/0x9c [drm]
lr : drm_bridge_hpd_enable+0x94/0x9c [drm]
sp : 89ef3740
x29: 89ef3740 x28: 09331f00 x27: 1000
x26: 0020 x25: 81148ed8 x24: 0a8fe000
x23: fffd x22: 05086348 x21: 81133ee0
x20: 0550d800 x19: 05086288 x18: 0006
x17:  x16: 896ef008 x15: 972891004260
x14: 2a1403e19400 x13: 972891004260 x12: 2a1403e19400
x11: 7100385f29400801 x10: 0aa0 x9 : 88112744
x8 : 00250b00 x7 : 0003 x6 : 0011
x5 :  x4 : bd986a48 x3 : 0001
x2 :  x1 :  x0 : 0025
Call trace:
  drm_bridge_hpd_enable+0x94/0x9c [drm]
  drm_bridge_connector_enable_hpd+0x2c/0x3c [drm_kms_helper]
  drm_kms_helper_poll_enable+0x94/0x10c [drm_kms_helper]
  drm_helper_probe_single_connector_modes+0x1a8/0x510 [drm_kms_helper]
  drm_client_modeset_probe+0x204/0x1190 [drm]
  __drm_fb_helper_initial_config_and_unlock+0x5c/0x4a4 [drm_kms_helper]
  drm_fb_helper_initial_config+0x54/0x6c [drm_kms_helper]
  drm_fbdev_client_hotplug+0xd0/0x140 [drm_kms_helper]
  drm_fbdev_generic_setup+0x90/0x154 [drm_kms_helper]
  dcss_kms_attach+0x1c8/0x254 [imx_dcss]
  dcss_drv_platform_probe+0x90/0xfc [imx_dcss]
  platform_probe+0x70/0xcc
  really_probe+0xc4/0x2e0
  __driver_probe_device+0x80/0xf0
  driver_probe_device+0xe0/0x164
  __device_attach_driver+0xc0/0x13c
  bus_for_each_drv+0x84/0xe0
  __device_attach+0xa4/0x1a0
  device_initial_probe+0x1c/0x30
  bus_probe_device+0xa4/0xb0
  deferred_probe_work_func+0x90/0xd0
  process_one_work+0x200/0x474
  worker_thread+0x74/0x43c
  kthread+0xfc/0x110
  ret_from_fork+0x10/0x20
---[ end trace  ]---

Reported-by: Laurentiu Palcu 
Fixes: c8268795c9a9 ("drm/probe-helper: enable and disable HPD on connectors")
Tested-by: Marek Szyprowski 
Tested-by: Chen-Yu Tsai 
Signed-off-by: Dmitry Baryshkov 
---

Changes since v1:
- Fixed drm_kms_helper_enable_hpd() to call enable_hpd() instead of
   disable_hpd().

---
  drivers/gpu/drm/drm_probe_helper.c | 110 +
  1 file changed, 63 insertions(+), 47 deletions(-)

diff --git a/drivers/gpu/drm/drm_probe_helper.c 
b/drivers/gpu/drm/drm_probe_helper.c
index 7973f2589ced..04754bb7b131 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -222,6 +222,45 @@ drm_connector_mode_valid(struct drm_connector *connector,
return ret;
  }
  
+static void drm_kms_helper_disable_hpd(struct drm_device *dev)

+{
+   struct drm_connector *connector;
+   struct drm_connector_list_iter conn_iter;
+
+   drm_connector_list_iter_begin(dev, _iter);
+   drm_for_each_connector_iter(connector, _iter) {
+   const struct drm_connector_helper_funcs *funcs =
+   connector->helper_private;
+
+   if (funcs && funcs->disable_hpd)
+   funcs->disable_hpd(connector);
+   }
+   drm_connector_list_iter_end(_iter);
+}
+
+static bool drm_kms_helper_enable_hpd(struct drm_device *dev)
+{
+   bool poll = false;
+   struct drm_connector *connector;
+   struct drm_connector_list_iter conn_iter;
+
+   drm_connector_list_iter_begin(dev, _iter);
+   drm_for_each_connector_iter(connector, _iter) {
+   const struct drm_connector_helper_funcs *funcs =
+   connector->helper_private;
+
+   if (funcs && funcs->enable_hpd)
+   funcs->enable_hpd(connector);
+
+   if (connector->polled & 

Re: [Intel-gfx] [PATCH v2] drm/probe_helper: sort out poll_running vs poll_enabled

2023-01-24 Thread Dmitry Baryshkov

On 20/01/2023 18:39, Laurent Pinchart wrote:

Hi Dmitry,

Thank you for the patch.

On Wed, Jan 18, 2023 at 01:39:05AM +0200, Dmitry Baryshkov wrote:

There are two flags attemting to guard connector polling:
poll_enabled and poll_running. While poll_enabled semantics is clearly
defined and fully adhered (mark that drm_kms_helper_poll_init() was
called and not finalized by the _fini() call), the poll_running flag
doesn't have such clearliness.

This flag is used only in drm_helper_probe_single_connector_modes() to
guard calling of drm_kms_helper_poll_enable, it doesn't guard the
drm_kms_helper_poll_fini(), etc. Change it to only be set if the polling
is actually running. Tie HPD enablement to this flag.

This fixes the following warning reported after merging the HPD series:

Hot plug detection already enabled
WARNING: CPU: 2 PID: 9 at drivers/gpu/drm/drm_bridge.c:1257 
drm_bridge_hpd_enable+0x94/0x9c [drm]
Modules linked in: videobuf2_memops snd_soc_simple_card 
snd_soc_simple_card_utils fsl_imx8_ddr_perf videobuf2_common snd_soc_imx_spdif 
adv7511 etnaviv imx8m_ddrc imx_dcss mc cec nwl_dsi gov
CPU: 2 PID: 9 Comm: kworker/u8:0 Not tainted 6.2.0-rc2-15208-g25b283acd578 #6
Hardware name: NXP i.MX8MQ EVK (DT)
Workqueue: events_unbound deferred_probe_work_func
pstate: 6005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : drm_bridge_hpd_enable+0x94/0x9c [drm]
lr : drm_bridge_hpd_enable+0x94/0x9c [drm]
sp : 89ef3740
x29: 89ef3740 x28: 09331f00 x27: 1000
x26: 0020 x25: 81148ed8 x24: 0a8fe000
x23: fffd x22: 05086348 x21: 81133ee0
x20: 0550d800 x19: 05086288 x18: 0006
x17:  x16: 896ef008 x15: 972891004260
x14: 2a1403e19400 x13: 972891004260 x12: 2a1403e19400
x11: 7100385f29400801 x10: 0aa0 x9 : 88112744
x8 : 00250b00 x7 : 0003 x6 : 0011
x5 :  x4 : bd986a48 x3 : 0001
x2 :  x1 :  x0 : 0025
Call trace:
  drm_bridge_hpd_enable+0x94/0x9c [drm]
  drm_bridge_connector_enable_hpd+0x2c/0x3c [drm_kms_helper]
  drm_kms_helper_poll_enable+0x94/0x10c [drm_kms_helper]
  drm_helper_probe_single_connector_modes+0x1a8/0x510 [drm_kms_helper]
  drm_client_modeset_probe+0x204/0x1190 [drm]
  __drm_fb_helper_initial_config_and_unlock+0x5c/0x4a4 [drm_kms_helper]
  drm_fb_helper_initial_config+0x54/0x6c [drm_kms_helper]
  drm_fbdev_client_hotplug+0xd0/0x140 [drm_kms_helper]
  drm_fbdev_generic_setup+0x90/0x154 [drm_kms_helper]
  dcss_kms_attach+0x1c8/0x254 [imx_dcss]
  dcss_drv_platform_probe+0x90/0xfc [imx_dcss]
  platform_probe+0x70/0xcc
  really_probe+0xc4/0x2e0
  __driver_probe_device+0x80/0xf0
  driver_probe_device+0xe0/0x164
  __device_attach_driver+0xc0/0x13c
  bus_for_each_drv+0x84/0xe0
  __device_attach+0xa4/0x1a0
  device_initial_probe+0x1c/0x30
  bus_probe_device+0xa4/0xb0
  deferred_probe_work_func+0x90/0xd0
  process_one_work+0x200/0x474
  worker_thread+0x74/0x43c
  kthread+0xfc/0x110
  ret_from_fork+0x10/0x20
---[ end trace  ]---

Reported-by: Laurentiu Palcu 
Fixes: c8268795c9a9 ("drm/probe-helper: enable and disable HPD on connectors")
Tested-by: Marek Szyprowski 
Tested-by: Chen-Yu Tsai 
Signed-off-by: Dmitry Baryshkov 


This fixes the issue on my Renesas boards.

Tested-by: Laurent Pinchart 

Please see below for a few comments.



[skipped two small comments, will fix them in v3]



@@ -886,7 +897,12 @@ EXPORT_SYMBOL(drm_kms_helper_poll_init);
   */
  void drm_kms_helper_poll_fini(struct drm_device *dev)
  {
-   drm_kms_helper_poll_disable_fini(dev, true);
+   if (!dev->mode_config.poll_enabled)
+   return;
+
+   drm_kms_helper_poll_disable(dev);
+
+   dev->mode_config.poll_enabled = false;


The fact that poll_enabled guard init/fini and poll_running guards
enable/disable is confusing :-S It would be nice if the poll_enable flag
matched the enable/disable function names. One option could be

- drm_kms_helper_poll_enable() -> drm_kms_helper_poll_resume()
- drm_kms_helper_poll_disable() -> drm_kms_helper_poll_suspend()
- drm_kms_helper_poll_init() -> drm_kms_helper_poll_enable()
- drm_kms_helper_poll_fini() -> drm_kms_helper_poll_disable()

This would align quite well with intended usage in drivers I think, the
current enable/disable functions are documented as being used by drivers
for suspend/resume, and the init()/fini() functions are documented as
"init and enable" and "disable and cleanup".

This isn't a candidate for this patch of course, it can be done on top.


Yes, but I'd extremely dislike renaming a function to use the name of 
the function that existed previously. It can lead to very confusing issue.


What do you think about keeping poll_init()/_fini() as is, reaming 
dev->mode_config.poll_enabled to poll_initialized, and renaming 
poll_enable()/disable() to 

Re: [Intel-gfx] [PATCH v2] drm/probe_helper: sort out poll_running vs poll_enabled

2023-01-24 Thread Jani Nikula
On Wed, 18 Jan 2023, Dmitry Baryshkov  wrote:
> There are two flags attemting to guard connector polling:
> poll_enabled and poll_running. While poll_enabled semantics is clearly
> defined and fully adhered (mark that drm_kms_helper_poll_init() was
> called and not finalized by the _fini() call), the poll_running flag
> doesn't have such clearliness.
>
> This flag is used only in drm_helper_probe_single_connector_modes() to
> guard calling of drm_kms_helper_poll_enable, it doesn't guard the
> drm_kms_helper_poll_fini(), etc. Change it to only be set if the polling
> is actually running. Tie HPD enablement to this flag.
>
> This fixes the following warning reported after merging the HPD series:
>
> Hot plug detection already enabled
> WARNING: CPU: 2 PID: 9 at drivers/gpu/drm/drm_bridge.c:1257 
> drm_bridge_hpd_enable+0x94/0x9c [drm]
> Modules linked in: videobuf2_memops snd_soc_simple_card 
> snd_soc_simple_card_utils fsl_imx8_ddr_perf videobuf2_common 
> snd_soc_imx_spdif adv7511 etnaviv imx8m_ddrc imx_dcss mc cec nwl_dsi gov
> CPU: 2 PID: 9 Comm: kworker/u8:0 Not tainted 6.2.0-rc2-15208-g25b283acd578 #6
> Hardware name: NXP i.MX8MQ EVK (DT)
> Workqueue: events_unbound deferred_probe_work_func
> pstate: 6005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : drm_bridge_hpd_enable+0x94/0x9c [drm]
> lr : drm_bridge_hpd_enable+0x94/0x9c [drm]
> sp : 89ef3740
> x29: 89ef3740 x28: 09331f00 x27: 1000
> x26: 0020 x25: 81148ed8 x24: 0a8fe000
> x23: fffd x22: 05086348 x21: 81133ee0
> x20: 0550d800 x19: 05086288 x18: 0006
> x17:  x16: 896ef008 x15: 972891004260
> x14: 2a1403e19400 x13: 972891004260 x12: 2a1403e19400
> x11: 7100385f29400801 x10: 0aa0 x9 : 88112744
> x8 : 00250b00 x7 : 0003 x6 : 0011
> x5 :  x4 : bd986a48 x3 : 0001
> x2 :  x1 :  x0 : 0025
> Call trace:
>  drm_bridge_hpd_enable+0x94/0x9c [drm]
>  drm_bridge_connector_enable_hpd+0x2c/0x3c [drm_kms_helper]
>  drm_kms_helper_poll_enable+0x94/0x10c [drm_kms_helper]
>  drm_helper_probe_single_connector_modes+0x1a8/0x510 [drm_kms_helper]
>  drm_client_modeset_probe+0x204/0x1190 [drm]
>  __drm_fb_helper_initial_config_and_unlock+0x5c/0x4a4 [drm_kms_helper]
>  drm_fb_helper_initial_config+0x54/0x6c [drm_kms_helper]
>  drm_fbdev_client_hotplug+0xd0/0x140 [drm_kms_helper]
>  drm_fbdev_generic_setup+0x90/0x154 [drm_kms_helper]
>  dcss_kms_attach+0x1c8/0x254 [imx_dcss]
>  dcss_drv_platform_probe+0x90/0xfc [imx_dcss]
>  platform_probe+0x70/0xcc
>  really_probe+0xc4/0x2e0
>  __driver_probe_device+0x80/0xf0
>  driver_probe_device+0xe0/0x164
>  __device_attach_driver+0xc0/0x13c
>  bus_for_each_drv+0x84/0xe0
>  __device_attach+0xa4/0x1a0
>  device_initial_probe+0x1c/0x30
>  bus_probe_device+0xa4/0xb0
>  deferred_probe_work_func+0x90/0xd0
>  process_one_work+0x200/0x474
>  worker_thread+0x74/0x43c
>  kthread+0xfc/0x110
>  ret_from_fork+0x10/0x20
> ---[ end trace  ]---
>
> Reported-by: Laurentiu Palcu 
> Fixes: c8268795c9a9 ("drm/probe-helper: enable and disable HPD on connectors")
> Tested-by: Marek Szyprowski 
> Tested-by: Chen-Yu Tsai 
> Signed-off-by: Dmitry Baryshkov 
> ---
>
> Changes since v1:
> - Fixed drm_kms_helper_enable_hpd() to call enable_hpd() instead of
>   disable_hpd().
>
> ---
>  drivers/gpu/drm/drm_probe_helper.c | 110 +
>  1 file changed, 63 insertions(+), 47 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_probe_helper.c 
> b/drivers/gpu/drm/drm_probe_helper.c
> index 7973f2589ced..04754bb7b131 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -222,6 +222,45 @@ drm_connector_mode_valid(struct drm_connector *connector,
>   return ret;
>  }
>  
> +static void drm_kms_helper_disable_hpd(struct drm_device *dev)
> +{
> + struct drm_connector *connector;
> + struct drm_connector_list_iter conn_iter;
> +
> + drm_connector_list_iter_begin(dev, _iter);
> + drm_for_each_connector_iter(connector, _iter) {
> + const struct drm_connector_helper_funcs *funcs =
> + connector->helper_private;
> +
> + if (funcs && funcs->disable_hpd)
> + funcs->disable_hpd(connector);
> + }
> + drm_connector_list_iter_end(_iter);
> +}
> +
> +static bool drm_kms_helper_enable_hpd(struct drm_device *dev)
> +{
> + bool poll = false;
> + struct drm_connector *connector;
> + struct drm_connector_list_iter conn_iter;
> +
> + drm_connector_list_iter_begin(dev, _iter);
> + drm_for_each_connector_iter(connector, _iter) {
> + const struct drm_connector_helper_funcs *funcs =
> + connector->helper_private;
> +
> + if (funcs && funcs->enable_hpd)
> +   

Re: [Intel-gfx] [PATCH v2] drm/probe_helper: sort out poll_running vs poll_enabled

2023-01-20 Thread Laurent Pinchart
Hi Dmitry,

Thank you for the patch.

On Wed, Jan 18, 2023 at 01:39:05AM +0200, Dmitry Baryshkov wrote:
> There are two flags attemting to guard connector polling:
> poll_enabled and poll_running. While poll_enabled semantics is clearly
> defined and fully adhered (mark that drm_kms_helper_poll_init() was
> called and not finalized by the _fini() call), the poll_running flag
> doesn't have such clearliness.
> 
> This flag is used only in drm_helper_probe_single_connector_modes() to
> guard calling of drm_kms_helper_poll_enable, it doesn't guard the
> drm_kms_helper_poll_fini(), etc. Change it to only be set if the polling
> is actually running. Tie HPD enablement to this flag.
> 
> This fixes the following warning reported after merging the HPD series:
> 
> Hot plug detection already enabled
> WARNING: CPU: 2 PID: 9 at drivers/gpu/drm/drm_bridge.c:1257 
> drm_bridge_hpd_enable+0x94/0x9c [drm]
> Modules linked in: videobuf2_memops snd_soc_simple_card 
> snd_soc_simple_card_utils fsl_imx8_ddr_perf videobuf2_common 
> snd_soc_imx_spdif adv7511 etnaviv imx8m_ddrc imx_dcss mc cec nwl_dsi gov
> CPU: 2 PID: 9 Comm: kworker/u8:0 Not tainted 6.2.0-rc2-15208-g25b283acd578 #6
> Hardware name: NXP i.MX8MQ EVK (DT)
> Workqueue: events_unbound deferred_probe_work_func
> pstate: 6005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : drm_bridge_hpd_enable+0x94/0x9c [drm]
> lr : drm_bridge_hpd_enable+0x94/0x9c [drm]
> sp : 89ef3740
> x29: 89ef3740 x28: 09331f00 x27: 1000
> x26: 0020 x25: 81148ed8 x24: 0a8fe000
> x23: fffd x22: 05086348 x21: 81133ee0
> x20: 0550d800 x19: 05086288 x18: 0006
> x17:  x16: 896ef008 x15: 972891004260
> x14: 2a1403e19400 x13: 972891004260 x12: 2a1403e19400
> x11: 7100385f29400801 x10: 0aa0 x9 : 88112744
> x8 : 00250b00 x7 : 0003 x6 : 0011
> x5 :  x4 : bd986a48 x3 : 0001
> x2 :  x1 :  x0 : 0025
> Call trace:
>  drm_bridge_hpd_enable+0x94/0x9c [drm]
>  drm_bridge_connector_enable_hpd+0x2c/0x3c [drm_kms_helper]
>  drm_kms_helper_poll_enable+0x94/0x10c [drm_kms_helper]
>  drm_helper_probe_single_connector_modes+0x1a8/0x510 [drm_kms_helper]
>  drm_client_modeset_probe+0x204/0x1190 [drm]
>  __drm_fb_helper_initial_config_and_unlock+0x5c/0x4a4 [drm_kms_helper]
>  drm_fb_helper_initial_config+0x54/0x6c [drm_kms_helper]
>  drm_fbdev_client_hotplug+0xd0/0x140 [drm_kms_helper]
>  drm_fbdev_generic_setup+0x90/0x154 [drm_kms_helper]
>  dcss_kms_attach+0x1c8/0x254 [imx_dcss]
>  dcss_drv_platform_probe+0x90/0xfc [imx_dcss]
>  platform_probe+0x70/0xcc
>  really_probe+0xc4/0x2e0
>  __driver_probe_device+0x80/0xf0
>  driver_probe_device+0xe0/0x164
>  __device_attach_driver+0xc0/0x13c
>  bus_for_each_drv+0x84/0xe0
>  __device_attach+0xa4/0x1a0
>  device_initial_probe+0x1c/0x30
>  bus_probe_device+0xa4/0xb0
>  deferred_probe_work_func+0x90/0xd0
>  process_one_work+0x200/0x474
>  worker_thread+0x74/0x43c
>  kthread+0xfc/0x110
>  ret_from_fork+0x10/0x20
> ---[ end trace  ]---
> 
> Reported-by: Laurentiu Palcu 
> Fixes: c8268795c9a9 ("drm/probe-helper: enable and disable HPD on connectors")
> Tested-by: Marek Szyprowski 
> Tested-by: Chen-Yu Tsai 
> Signed-off-by: Dmitry Baryshkov 

This fixes the issue on my Renesas boards.

Tested-by: Laurent Pinchart 

Please see below for a few comments.

> ---
> 
> Changes since v1:
> - Fixed drm_kms_helper_enable_hpd() to call enable_hpd() instead of
>   disable_hpd().
> 
> ---
>  drivers/gpu/drm/drm_probe_helper.c | 110 +
>  1 file changed, 63 insertions(+), 47 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_probe_helper.c 
> b/drivers/gpu/drm/drm_probe_helper.c
> index 7973f2589ced..04754bb7b131 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -222,6 +222,45 @@ drm_connector_mode_valid(struct drm_connector *connector,
>   return ret;
>  }
>  
> +static void drm_kms_helper_disable_hpd(struct drm_device *dev)
> +{
> + struct drm_connector *connector;
> + struct drm_connector_list_iter conn_iter;
> +
> + drm_connector_list_iter_begin(dev, _iter);
> + drm_for_each_connector_iter(connector, _iter) {
> + const struct drm_connector_helper_funcs *funcs =
> + connector->helper_private;
> +
> + if (funcs && funcs->disable_hpd)
> + funcs->disable_hpd(connector);
> + }
> + drm_connector_list_iter_end(_iter);
> +}
> +
> +static bool drm_kms_helper_enable_hpd(struct drm_device *dev)
> +{
> + bool poll = false;
> + struct drm_connector *connector;
> + struct drm_connector_list_iter conn_iter;
> +
> + drm_connector_list_iter_begin(dev, _iter);
> + drm_for_each_connector_iter(connector, _iter) {

[Intel-gfx] [PATCH v2] drm/probe_helper: sort out poll_running vs poll_enabled

2023-01-18 Thread Dmitry Baryshkov
There are two flags attemting to guard connector polling:
poll_enabled and poll_running. While poll_enabled semantics is clearly
defined and fully adhered (mark that drm_kms_helper_poll_init() was
called and not finalized by the _fini() call), the poll_running flag
doesn't have such clearliness.

This flag is used only in drm_helper_probe_single_connector_modes() to
guard calling of drm_kms_helper_poll_enable, it doesn't guard the
drm_kms_helper_poll_fini(), etc. Change it to only be set if the polling
is actually running. Tie HPD enablement to this flag.

This fixes the following warning reported after merging the HPD series:

Hot plug detection already enabled
WARNING: CPU: 2 PID: 9 at drivers/gpu/drm/drm_bridge.c:1257 
drm_bridge_hpd_enable+0x94/0x9c [drm]
Modules linked in: videobuf2_memops snd_soc_simple_card 
snd_soc_simple_card_utils fsl_imx8_ddr_perf videobuf2_common snd_soc_imx_spdif 
adv7511 etnaviv imx8m_ddrc imx_dcss mc cec nwl_dsi gov
CPU: 2 PID: 9 Comm: kworker/u8:0 Not tainted 6.2.0-rc2-15208-g25b283acd578 #6
Hardware name: NXP i.MX8MQ EVK (DT)
Workqueue: events_unbound deferred_probe_work_func
pstate: 6005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : drm_bridge_hpd_enable+0x94/0x9c [drm]
lr : drm_bridge_hpd_enable+0x94/0x9c [drm]
sp : 89ef3740
x29: 89ef3740 x28: 09331f00 x27: 1000
x26: 0020 x25: 81148ed8 x24: 0a8fe000
x23: fffd x22: 05086348 x21: 81133ee0
x20: 0550d800 x19: 05086288 x18: 0006
x17:  x16: 896ef008 x15: 972891004260
x14: 2a1403e19400 x13: 972891004260 x12: 2a1403e19400
x11: 7100385f29400801 x10: 0aa0 x9 : 88112744
x8 : 00250b00 x7 : 0003 x6 : 0011
x5 :  x4 : bd986a48 x3 : 0001
x2 :  x1 :  x0 : 0025
Call trace:
 drm_bridge_hpd_enable+0x94/0x9c [drm]
 drm_bridge_connector_enable_hpd+0x2c/0x3c [drm_kms_helper]
 drm_kms_helper_poll_enable+0x94/0x10c [drm_kms_helper]
 drm_helper_probe_single_connector_modes+0x1a8/0x510 [drm_kms_helper]
 drm_client_modeset_probe+0x204/0x1190 [drm]
 __drm_fb_helper_initial_config_and_unlock+0x5c/0x4a4 [drm_kms_helper]
 drm_fb_helper_initial_config+0x54/0x6c [drm_kms_helper]
 drm_fbdev_client_hotplug+0xd0/0x140 [drm_kms_helper]
 drm_fbdev_generic_setup+0x90/0x154 [drm_kms_helper]
 dcss_kms_attach+0x1c8/0x254 [imx_dcss]
 dcss_drv_platform_probe+0x90/0xfc [imx_dcss]
 platform_probe+0x70/0xcc
 really_probe+0xc4/0x2e0
 __driver_probe_device+0x80/0xf0
 driver_probe_device+0xe0/0x164
 __device_attach_driver+0xc0/0x13c
 bus_for_each_drv+0x84/0xe0
 __device_attach+0xa4/0x1a0
 device_initial_probe+0x1c/0x30
 bus_probe_device+0xa4/0xb0
 deferred_probe_work_func+0x90/0xd0
 process_one_work+0x200/0x474
 worker_thread+0x74/0x43c
 kthread+0xfc/0x110
 ret_from_fork+0x10/0x20
---[ end trace  ]---

Reported-by: Laurentiu Palcu 
Fixes: c8268795c9a9 ("drm/probe-helper: enable and disable HPD on connectors")
Tested-by: Marek Szyprowski 
Tested-by: Chen-Yu Tsai 
Signed-off-by: Dmitry Baryshkov 
---

Changes since v1:
- Fixed drm_kms_helper_enable_hpd() to call enable_hpd() instead of
  disable_hpd().

---
 drivers/gpu/drm/drm_probe_helper.c | 110 +
 1 file changed, 63 insertions(+), 47 deletions(-)

diff --git a/drivers/gpu/drm/drm_probe_helper.c 
b/drivers/gpu/drm/drm_probe_helper.c
index 7973f2589ced..04754bb7b131 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -222,6 +222,45 @@ drm_connector_mode_valid(struct drm_connector *connector,
return ret;
 }
 
+static void drm_kms_helper_disable_hpd(struct drm_device *dev)
+{
+   struct drm_connector *connector;
+   struct drm_connector_list_iter conn_iter;
+
+   drm_connector_list_iter_begin(dev, _iter);
+   drm_for_each_connector_iter(connector, _iter) {
+   const struct drm_connector_helper_funcs *funcs =
+   connector->helper_private;
+
+   if (funcs && funcs->disable_hpd)
+   funcs->disable_hpd(connector);
+   }
+   drm_connector_list_iter_end(_iter);
+}
+
+static bool drm_kms_helper_enable_hpd(struct drm_device *dev)
+{
+   bool poll = false;
+   struct drm_connector *connector;
+   struct drm_connector_list_iter conn_iter;
+
+   drm_connector_list_iter_begin(dev, _iter);
+   drm_for_each_connector_iter(connector, _iter) {
+   const struct drm_connector_helper_funcs *funcs =
+   connector->helper_private;
+
+   if (funcs && funcs->enable_hpd)
+   funcs->enable_hpd(connector);
+
+   if (connector->polled & (DRM_CONNECTOR_POLL_CONNECT |
+DRM_CONNECTOR_POLL_DISCONNECT))
+   poll = true;
+  

Re: [Intel-gfx] [PATCH v2] drm/probe_helper: sort out poll_running vs poll_enabled

2023-01-18 Thread Laurentiu Palcu
On Wed, Jan 18, 2023 at 01:39:05AM +0200, Dmitry Baryshkov wrote:
> There are two flags attemting to guard connector polling:
> poll_enabled and poll_running. While poll_enabled semantics is clearly
> defined and fully adhered (mark that drm_kms_helper_poll_init() was
> called and not finalized by the _fini() call), the poll_running flag
> doesn't have such clearliness.
> 
> This flag is used only in drm_helper_probe_single_connector_modes() to
> guard calling of drm_kms_helper_poll_enable, it doesn't guard the
> drm_kms_helper_poll_fini(), etc. Change it to only be set if the polling
> is actually running. Tie HPD enablement to this flag.
> 
> This fixes the following warning reported after merging the HPD series:
> 
> Hot plug detection already enabled
> WARNING: CPU: 2 PID: 9 at drivers/gpu/drm/drm_bridge.c:1257 
> drm_bridge_hpd_enable+0x94/0x9c [drm]
> Modules linked in: videobuf2_memops snd_soc_simple_card 
> snd_soc_simple_card_utils fsl_imx8_ddr_perf videobuf2_common 
> snd_soc_imx_spdif adv7511 etnaviv imx8m_ddrc imx_dcss mc cec nwl_dsi gov
> CPU: 2 PID: 9 Comm: kworker/u8:0 Not tainted 6.2.0-rc2-15208-g25b283acd578 #6
> Hardware name: NXP i.MX8MQ EVK (DT)
> Workqueue: events_unbound deferred_probe_work_func
> pstate: 6005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : drm_bridge_hpd_enable+0x94/0x9c [drm]
> lr : drm_bridge_hpd_enable+0x94/0x9c [drm]
> sp : 89ef3740
> x29: 89ef3740 x28: 09331f00 x27: 1000
> x26: 0020 x25: 81148ed8 x24: 0a8fe000
> x23: fffd x22: 05086348 x21: 81133ee0
> x20: 0550d800 x19: 05086288 x18: 0006
> x17:  x16: 896ef008 x15: 972891004260
> x14: 2a1403e19400 x13: 972891004260 x12: 2a1403e19400
> x11: 7100385f29400801 x10: 0aa0 x9 : 88112744
> x8 : 00250b00 x7 : 0003 x6 : 0011
> x5 :  x4 : bd986a48 x3 : 0001
> x2 :  x1 :  x0 : 0025
> Call trace:
>  drm_bridge_hpd_enable+0x94/0x9c [drm]
>  drm_bridge_connector_enable_hpd+0x2c/0x3c [drm_kms_helper]
>  drm_kms_helper_poll_enable+0x94/0x10c [drm_kms_helper]
>  drm_helper_probe_single_connector_modes+0x1a8/0x510 [drm_kms_helper]
>  drm_client_modeset_probe+0x204/0x1190 [drm]
>  __drm_fb_helper_initial_config_and_unlock+0x5c/0x4a4 [drm_kms_helper]
>  drm_fb_helper_initial_config+0x54/0x6c [drm_kms_helper]
>  drm_fbdev_client_hotplug+0xd0/0x140 [drm_kms_helper]
>  drm_fbdev_generic_setup+0x90/0x154 [drm_kms_helper]
>  dcss_kms_attach+0x1c8/0x254 [imx_dcss]
>  dcss_drv_platform_probe+0x90/0xfc [imx_dcss]
>  platform_probe+0x70/0xcc
>  really_probe+0xc4/0x2e0
>  __driver_probe_device+0x80/0xf0
>  driver_probe_device+0xe0/0x164
>  __device_attach_driver+0xc0/0x13c
>  bus_for_each_drv+0x84/0xe0
>  __device_attach+0xa4/0x1a0
>  device_initial_probe+0x1c/0x30
>  bus_probe_device+0xa4/0xb0
>  deferred_probe_work_func+0x90/0xd0
>  process_one_work+0x200/0x474
>  worker_thread+0x74/0x43c
>  kthread+0xfc/0x110
>  ret_from_fork+0x10/0x20
> ---[ end trace  ]---
> 
> Reported-by: Laurentiu Palcu 
> Fixes: c8268795c9a9 ("drm/probe-helper: enable and disable HPD on connectors")
> Tested-by: Marek Szyprowski 
> Tested-by: Chen-Yu Tsai 
> Signed-off-by: Dmitry Baryshkov 

I gave this a test and the warning is gone. Also, HPD works as expected.

Acked-by: Laurentiu Palcu 
Tested-by: Laurentiu Palcu 

Cheers,
Laurentiu

> ---
> 
> Changes since v1:
> - Fixed drm_kms_helper_enable_hpd() to call enable_hpd() instead of
>   disable_hpd().
> 
> ---
>  drivers/gpu/drm/drm_probe_helper.c | 110 +
>  1 file changed, 63 insertions(+), 47 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_probe_helper.c 
> b/drivers/gpu/drm/drm_probe_helper.c
> index 7973f2589ced..04754bb7b131 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -222,6 +222,45 @@ drm_connector_mode_valid(struct drm_connector *connector,
>   return ret;
>  }
>  
> +static void drm_kms_helper_disable_hpd(struct drm_device *dev)
> +{
> + struct drm_connector *connector;
> + struct drm_connector_list_iter conn_iter;
> +
> + drm_connector_list_iter_begin(dev, _iter);
> + drm_for_each_connector_iter(connector, _iter) {
> + const struct drm_connector_helper_funcs *funcs =
> + connector->helper_private;
> +
> + if (funcs && funcs->disable_hpd)
> + funcs->disable_hpd(connector);
> + }
> + drm_connector_list_iter_end(_iter);
> +}
> +
> +static bool drm_kms_helper_enable_hpd(struct drm_device *dev)
> +{
> + bool poll = false;
> + struct drm_connector *connector;
> + struct drm_connector_list_iter conn_iter;
> +
> + drm_connector_list_iter_begin(dev, _iter);
> + drm_for_each_connector_iter(connector, _iter) {