* [PATCH] drm/bridge: analogix: protect power when get_modes or detect
@ 2016-10-12 10:00 Mark Yao
[not found] ` <57FE0EF5.7010207@rock-chips.com>
2016-10-13 1:50 ` [PATCH v2] " Mark Yao
0 siblings, 2 replies; 5+ messages in thread
From: Mark Yao @ 2016-10-12 10:00 UTC (permalink / raw)
To: linux-arm-kernel
The drm callback ->detect and ->get_modes seems is not power safe,
they may be called when device is power off, do register access on
detect or get_modes will cause system die.
Here is the path call ->detect before analogix_dp power on
[<ffffff800843babc>] analogix_dp_detect+0x44/0xdc
[<ffffff80083fd840>] drm_helper_probe_single_connector_modes_merge_bits+0xe8/0x41c
[<ffffff80083fdb84>] drm_helper_probe_single_connector_modes+0x10/0x18
[<ffffff8008418d24>] drm_mode_getconnector+0xf4/0x304
[<ffffff800840cff0>] drm_ioctl+0x23c/0x390
[<ffffff80081a8adc>] do_vfs_ioctl+0x4b8/0x58c
[<ffffff80081a8c10>] SyS_ioctl+0x60/0x88
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Cc: "Ville Syrj?l?" <ville.syrjala@linux.intel.com>
Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
---
drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 28 ++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index efac8ab..09dece2 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1062,6 +1062,13 @@ int analogix_dp_get_modes(struct drm_connector *connector)
return 0;
}
+ if (dp->dpms_mode != DRM_MODE_DPMS_ON) {
+ pm_runtime_get_sync(dp->dev);
+
+ if (dp->plat_data->power_on)
+ dp->plat_data->power_on(dp->plat_data);
+ }
+
if (analogix_dp_handle_edid(dp) == 0) {
drm_mode_connector_update_edid_property(&dp->connector, edid);
num_modes += drm_add_edid_modes(&dp->connector, edid);
@@ -1073,6 +1080,13 @@ int analogix_dp_get_modes(struct drm_connector *connector)
if (dp->plat_data->get_modes)
num_modes += dp->plat_data->get_modes(dp->plat_data, connector);
+ if (dp->dpms_mode != DRM_MODE_DPMS_ON) {
+ if (dp->plat_data->power_off)
+ dp->plat_data->power_off(dp->plat_data);
+
+ pm_runtime_put_sync(dp->dev);
+ }
+
ret = analogix_dp_prepare_panel(dp, false, false);
if (ret)
DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
@@ -1106,9 +1120,23 @@ analogix_dp_detect(struct drm_connector *connector, bool force)
return connector_status_disconnected;
}
+ if (dp->dpms_mode != DRM_MODE_DPMS_ON) {
+ pm_runtime_get_sync(dp->dev);
+
+ if (dp->plat_data->power_on)
+ dp->plat_data->power_on(dp->plat_data);
+ }
+
if (!analogix_dp_detect_hpd(dp))
status = connector_status_connected;
+ if (dp->dpms_mode != DRM_MODE_DPMS_ON) {
+ if (dp->plat_data->power_off)
+ dp->plat_data->power_off(dp->plat_data);
+
+ pm_runtime_put_sync(dp->dev);
+ }
+
ret = analogix_dp_prepare_panel(dp, false, false);
if (ret)
DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
--
1.9.1
^ permalink raw reply related [flat|nested] 5+ messages in thread[parent not found: <57FE0EF5.7010207@rock-chips.com>]
* Question: Re: [PATCH] drm/bridge: analogix: protect power when get_modes or detect
[not found] ` <57FE0EF5.7010207@rock-chips.com>
@ 2016-10-12 14:51 ` Sean Paul
2016-10-13 1:56 ` Mark yao
0 siblings, 1 reply; 5+ messages in thread
From: Sean Paul @ 2016-10-12 14:51 UTC (permalink / raw)
To: linux-arm-kernel
On Wed, Oct 12, 2016 at 6:22 AM, Mark yao <mark.yao@rock-chips.com> wrote:
>
> I'm not familiar with the analogix driver, maybe use a power reference count
> would better then direct power on/off analogix_dp.
>
> Does anyone has the idea to protect detect and get_modes context?
>
I'm not sure a reference count is going to help here. The common
pattern is to call detect() followed by get_modes() and then modeset.
However, it's not guaranteed that any one of those functions will be
called after the other. So, if you leave things on after detect or
get_modes, you might be wasting power (or worse).
I recently ran into this exact problem with a panel we're using. Check
out "0b8b059a7: drm/bridge: analogix_dp: Ensure the panel is properly
prepared/unprepared". Perhaps you can piggyback on that function to
add your pm_runtime and plat_data callbacks (since using dpms_mode
might be racey).
Sean
> I found many other connector driver also direct access register on detect or
> get_modes, no problem for it?
>
> On 2016?10?12? 18:00, Mark Yao wrote:
>
> The drm callback ->detect and ->get_modes seems is not power safe,
> they may be called when device is power off, do register access on
> detect or get_modes will cause system die.
>
> Here is the path call ->detect before analogix_dp power on
> [<ffffff800843babc>] analogix_dp_detect+0x44/0xdc
> [<ffffff80083fd840>]
> drm_helper_probe_single_connector_modes_merge_bits+0xe8/0x41c
> [<ffffff80083fdb84>] drm_helper_probe_single_connector_modes+0x10/0x18
> [<ffffff8008418d24>] drm_mode_getconnector+0xf4/0x304
> [<ffffff800840cff0>] drm_ioctl+0x23c/0x390
> [<ffffff80081a8adc>] do_vfs_ioctl+0x4b8/0x58c
> [<ffffff80081a8c10>] SyS_ioctl+0x60/0x88
>
> Cc: Inki Dae <inki.dae@samsung.com>
> Cc: Sean Paul <seanpaul@chromium.org>
> Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
> Cc: "Ville Syrj?l?" <ville.syrjala@linux.intel.com>
>
> Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
> ---
> drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 28
> ++++++++++++++++++++++
> 1 file changed, 28 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index efac8ab..09dece2 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -1062,6 +1062,13 @@ int analogix_dp_get_modes(struct drm_connector
> *connector)
> return 0;
> }
>
> + if (dp->dpms_mode != DRM_MODE_DPMS_ON) {
> + pm_runtime_get_sync(dp->dev);
> +
> + if (dp->plat_data->power_on)
> + dp->plat_data->power_on(dp->plat_data);
> + }
> +
> if (analogix_dp_handle_edid(dp) == 0) {
> drm_mode_connector_update_edid_property(&dp->connector, edid);
> num_modes += drm_add_edid_modes(&dp->connector, edid);
> @@ -1073,6 +1080,13 @@ int analogix_dp_get_modes(struct drm_connector
> *connector)
> if (dp->plat_data->get_modes)
> num_modes += dp->plat_data->get_modes(dp->plat_data, connector);
>
> + if (dp->dpms_mode != DRM_MODE_DPMS_ON) {
> + if (dp->plat_data->power_off)
> + dp->plat_data->power_off(dp->plat_data);
> +
> + pm_runtime_put_sync(dp->dev);
> + }
> +
> ret = analogix_dp_prepare_panel(dp, false, false);
> if (ret)
> DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
> @@ -1106,9 +1120,23 @@ analogix_dp_detect(struct drm_connector *connector,
> bool force)
> return connector_status_disconnected;
> }
>
> + if (dp->dpms_mode != DRM_MODE_DPMS_ON) {
> + pm_runtime_get_sync(dp->dev);
> +
> + if (dp->plat_data->power_on)
> + dp->plat_data->power_on(dp->plat_data);
> + }
> +
> if (!analogix_dp_detect_hpd(dp))
> status = connector_status_connected;
>
> + if (dp->dpms_mode != DRM_MODE_DPMS_ON) {
> + if (dp->plat_data->power_off)
> + dp->plat_data->power_off(dp->plat_data);
> +
> + pm_runtime_put_sync(dp->dev);
> + }
> +
> ret = analogix_dp_prepare_panel(dp, false, false);
> if (ret)
> DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
>
>
>
> --
> ?ark Yao
^ permalink raw reply [flat|nested] 5+ messages in thread* Question: Re: [PATCH] drm/bridge: analogix: protect power when get_modes or detect
2016-10-12 14:51 ` Question: " Sean Paul
@ 2016-10-13 1:56 ` Mark yao
0 siblings, 0 replies; 5+ messages in thread
From: Mark yao @ 2016-10-13 1:56 UTC (permalink / raw)
To: linux-arm-kernel
On 2016?10?12? 22:51, Sean Paul wrote:
> On Wed, Oct 12, 2016 at 6:22 AM, Mark yao <mark.yao@rock-chips.com> wrote:
>> I'm not familiar with the analogix driver, maybe use a power reference count
>> would better then direct power on/off analogix_dp.
>>
>> Does anyone has the idea to protect detect and get_modes context?
>>
> I'm not sure a reference count is going to help here. The common
> pattern is to call detect() followed by get_modes() and then modeset.
> However, it's not guaranteed that any one of those functions will be
> called after the other. So, if you leave things on after detect or
> get_modes, you might be wasting power (or worse).
>
> I recently ran into this exact problem with a panel we're using. Check
> out "0b8b059a7: drm/bridge: analogix_dp: Ensure the panel is properly
> prepared/unprepared". Perhaps you can piggyback on that function to
> add your pm_runtime and plat_data callbacks (since using dpms_mode
> might be racey).
>
> Sean
Hi Sean
Thanks for your advice.
I re-test the detect and get_modes, only use pm_runtime_get/put also can
fix my problem.
without plat_data callbacks can avoid race to dpms_mode.
I had send v2 patch, you can review it.
Thanks.
>
>> I found many other connector driver also direct access register on detect or
>> get_modes, no problem for it?
>>
>> On 2016?10?12? 18:00, Mark Yao wrote:
>>
>> The drm callback ->detect and ->get_modes seems is not power safe,
>> they may be called when device is power off, do register access on
>> detect or get_modes will cause system die.
>>
>> Here is the path call ->detect before analogix_dp power on
>> [<ffffff800843babc>] analogix_dp_detect+0x44/0xdc
>> [<ffffff80083fd840>]
>> drm_helper_probe_single_connector_modes_merge_bits+0xe8/0x41c
>> [<ffffff80083fdb84>] drm_helper_probe_single_connector_modes+0x10/0x18
>> [<ffffff8008418d24>] drm_mode_getconnector+0xf4/0x304
>> [<ffffff800840cff0>] drm_ioctl+0x23c/0x390
>> [<ffffff80081a8adc>] do_vfs_ioctl+0x4b8/0x58c
>> [<ffffff80081a8c10>] SyS_ioctl+0x60/0x88
>>
>> Cc: Inki Dae <inki.dae@samsung.com>
>> Cc: Sean Paul <seanpaul@chromium.org>
>> Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>> Cc: "Ville Syrj?l?" <ville.syrjala@linux.intel.com>
>>
>> Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
>> ---
>> drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 28
>> ++++++++++++++++++++++
>> 1 file changed, 28 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> index efac8ab..09dece2 100644
>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> @@ -1062,6 +1062,13 @@ int analogix_dp_get_modes(struct drm_connector
>> *connector)
>> return 0;
>> }
>>
>> + if (dp->dpms_mode != DRM_MODE_DPMS_ON) {
>> + pm_runtime_get_sync(dp->dev);
>> +
>> + if (dp->plat_data->power_on)
>> + dp->plat_data->power_on(dp->plat_data);
>> + }
>> +
>> if (analogix_dp_handle_edid(dp) == 0) {
>> drm_mode_connector_update_edid_property(&dp->connector, edid);
>> num_modes += drm_add_edid_modes(&dp->connector, edid);
>> @@ -1073,6 +1080,13 @@ int analogix_dp_get_modes(struct drm_connector
>> *connector)
>> if (dp->plat_data->get_modes)
>> num_modes += dp->plat_data->get_modes(dp->plat_data, connector);
>>
>> + if (dp->dpms_mode != DRM_MODE_DPMS_ON) {
>> + if (dp->plat_data->power_off)
>> + dp->plat_data->power_off(dp->plat_data);
>> +
>> + pm_runtime_put_sync(dp->dev);
>> + }
>> +
>> ret = analogix_dp_prepare_panel(dp, false, false);
>> if (ret)
>> DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
>> @@ -1106,9 +1120,23 @@ analogix_dp_detect(struct drm_connector *connector,
>> bool force)
>> return connector_status_disconnected;
>> }
>>
>> + if (dp->dpms_mode != DRM_MODE_DPMS_ON) {
>> + pm_runtime_get_sync(dp->dev);
>> +
>> + if (dp->plat_data->power_on)
>> + dp->plat_data->power_on(dp->plat_data);
>> + }
>> +
>> if (!analogix_dp_detect_hpd(dp))
>> status = connector_status_connected;
>>
>> + if (dp->dpms_mode != DRM_MODE_DPMS_ON) {
>> + if (dp->plat_data->power_off)
>> + dp->plat_data->power_off(dp->plat_data);
>> +
>> + pm_runtime_put_sync(dp->dev);
>> + }
>> +
>> ret = analogix_dp_prepare_panel(dp, false, false);
>> if (ret)
>> DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
>>
>>
>>
>> --
>> ?ark Yao
>
>
--
?ark Yao
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v2] drm/bridge: analogix: protect power when get_modes or detect
2016-10-12 10:00 [PATCH] drm/bridge: analogix: protect power when get_modes or detect Mark Yao
[not found] ` <57FE0EF5.7010207@rock-chips.com>
@ 2016-10-13 1:50 ` Mark Yao
2016-10-13 19:15 ` Sean Paul
1 sibling, 1 reply; 5+ messages in thread
From: Mark Yao @ 2016-10-13 1:50 UTC (permalink / raw)
To: linux-arm-kernel
The drm callback ->detect and ->get_modes seems is not power safe,
they may be called when device is power off, do register access on
detect or get_modes will cause system die.
Here is the path call ->detect before analogix_dp power on
[<ffffff800843babc>] analogix_dp_detect+0x44/0xdc
[<ffffff80083fd840>] drm_helper_probe_single_connector_modes_merge_bits+0xe8/0x41c
[<ffffff80083fdb84>] drm_helper_probe_single_connector_modes+0x10/0x18
[<ffffff8008418d24>] drm_mode_getconnector+0xf4/0x304
[<ffffff800840cff0>] drm_ioctl+0x23c/0x390
[<ffffff80081a8adc>] do_vfs_ioctl+0x4b8/0x58c
[<ffffff80081a8c10>] SyS_ioctl+0x60/0x88
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Cc: "Ville Syrj?l?" <ville.syrjala@linux.intel.com>
Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
---
Changes in v2:
- remove sub device power on/off callback, use pm_runtime_get/put is enough
to fix my problem, so will can avoid race to dpms.
drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index efac8ab..ff2d328 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1062,11 +1062,15 @@ int analogix_dp_get_modes(struct drm_connector *connector)
return 0;
}
+ pm_runtime_get_sync(dp->dev);
+
if (analogix_dp_handle_edid(dp) == 0) {
drm_mode_connector_update_edid_property(&dp->connector, edid);
num_modes += drm_add_edid_modes(&dp->connector, edid);
}
+ pm_runtime_put(dp->dev);
+
if (dp->plat_data->panel)
num_modes += drm_panel_get_modes(dp->plat_data->panel);
@@ -1106,9 +1110,13 @@ analogix_dp_detect(struct drm_connector *connector, bool force)
return connector_status_disconnected;
}
+ pm_runtime_get_sync(dp->dev);
+
if (!analogix_dp_detect_hpd(dp))
status = connector_status_connected;
+ pm_runtime_put(dp->dev);
+
ret = analogix_dp_prepare_panel(dp, false, false);
if (ret)
DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
--
1.9.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v2] drm/bridge: analogix: protect power when get_modes or detect
2016-10-13 1:50 ` [PATCH v2] " Mark Yao
@ 2016-10-13 19:15 ` Sean Paul
0 siblings, 0 replies; 5+ messages in thread
From: Sean Paul @ 2016-10-13 19:15 UTC (permalink / raw)
To: linux-arm-kernel
On Wed, Oct 12, 2016 at 9:50 PM, Mark Yao <mark.yao@rock-chips.com> wrote:
> The drm callback ->detect and ->get_modes seems is not power safe,
> they may be called when device is power off, do register access on
> detect or get_modes will cause system die.
>
> Here is the path call ->detect before analogix_dp power on
> [<ffffff800843babc>] analogix_dp_detect+0x44/0xdc
> [<ffffff80083fd840>] drm_helper_probe_single_connector_modes_merge_bits+0xe8/0x41c
> [<ffffff80083fdb84>] drm_helper_probe_single_connector_modes+0x10/0x18
> [<ffffff8008418d24>] drm_mode_getconnector+0xf4/0x304
> [<ffffff800840cff0>] drm_ioctl+0x23c/0x390
> [<ffffff80081a8adc>] do_vfs_ioctl+0x4b8/0x58c
> [<ffffff80081a8c10>] SyS_ioctl+0x60/0x88
>
> Cc: Inki Dae <inki.dae@samsung.com>
> Cc: Sean Paul <seanpaul@chromium.org>
> Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
> Cc: "Ville Syrj?l?" <ville.syrjala@linux.intel.com>
>
> Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
Thanks for revising, this is much better.
Reviewed-by: Sean Paul <seanpaul@chromium.org>
> ---
> Changes in v2:
> - remove sub device power on/off callback, use pm_runtime_get/put is enough
> to fix my problem, so will can avoid race to dpms.
>
> drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index efac8ab..ff2d328 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -1062,11 +1062,15 @@ int analogix_dp_get_modes(struct drm_connector *connector)
> return 0;
> }
>
> + pm_runtime_get_sync(dp->dev);
> +
> if (analogix_dp_handle_edid(dp) == 0) {
> drm_mode_connector_update_edid_property(&dp->connector, edid);
> num_modes += drm_add_edid_modes(&dp->connector, edid);
> }
>
> + pm_runtime_put(dp->dev);
> +
> if (dp->plat_data->panel)
> num_modes += drm_panel_get_modes(dp->plat_data->panel);
>
> @@ -1106,9 +1110,13 @@ analogix_dp_detect(struct drm_connector *connector, bool force)
> return connector_status_disconnected;
> }
>
> + pm_runtime_get_sync(dp->dev);
> +
> if (!analogix_dp_detect_hpd(dp))
> status = connector_status_connected;
>
> + pm_runtime_put(dp->dev);
> +
> ret = analogix_dp_prepare_panel(dp, false, false);
> if (ret)
> DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
> --
> 1.9.1
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2016-10-13 19:15 UTC | newest]
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2016-10-12 10:00 [PATCH] drm/bridge: analogix: protect power when get_modes or detect Mark Yao
[not found] ` <57FE0EF5.7010207@rock-chips.com>
2016-10-12 14:51 ` Question: " Sean Paul
2016-10-13 1:56 ` Mark yao
2016-10-13 1:50 ` [PATCH v2] " Mark Yao
2016-10-13 19:15 ` Sean Paul
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