* [PATCH] gpu/drm/bridge/cadence: avoid flush_scheduled_work() usage
@ 2022-06-10 14:30 Tetsuo Handa
2022-06-10 14:35 ` [PATCH v2] " Tetsuo Handa
0 siblings, 1 reply; 4+ messages in thread
From: Tetsuo Handa @ 2022-06-10 14:30 UTC (permalink / raw)
To: Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, David Airlie, Daniel Vetter
Cc: DRI
Use local wq in order to avoid flush_scheduled_work() usage.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
Please see commit c4f135d643823a86 ("workqueue: Wrap flush_workqueue()
using a macro") for background.
This is a blind conversion, and is only compile tested.
.../drm/bridge/cadence/cdns-mhdp8546-core.c | 30 ++++++++++++++++---
.../drm/bridge/cadence/cdns-mhdp8546-core.h | 2 ++
.../drm/bridge/cadence/cdns-mhdp8546-hdcp.c | 16 +++++-----
3 files changed, 36 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
index 67f0f444b4e8..1d7c6af66217 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -53,6 +53,8 @@
#include "cdns-mhdp8546-hdcp.h"
#include "cdns-mhdp8546-j721e.h"
+struct workqueue_struct *cadence_mhdp_wq;
+
static int cdns_mhdp_mailbox_read(struct cdns_mhdp_device *mhdp)
{
int ret, empty;
@@ -2049,7 +2051,7 @@ static void cdns_mhdp_atomic_enable(struct drm_bridge *bridge,
out:
mutex_unlock(&mhdp->link_mutex);
if (ret < 0)
- schedule_work(&mhdp->modeset_retry_work);
+ queue_work(cadence_mhdp_wq, &mhdp->modeset_retry_work);
}
static void cdns_mhdp_atomic_disable(struct drm_bridge *bridge,
@@ -2373,7 +2375,7 @@ static irqreturn_t cdns_mhdp_irq_handler(int irq, void *data)
spin_unlock(&mhdp->start_lock);
if (bridge_attached && (sw_ev0 & CDNS_DPTX_HPD)) {
- schedule_work(&mhdp->hpd_work);
+ queue_work(cadence_mhdp_wq, &mhdp->hpd_work);
}
if (sw_ev0 & ~CDNS_DPTX_HPD) {
@@ -2413,7 +2415,7 @@ static void cdns_mhdp_hpd_work(struct work_struct *work)
ret = cdns_mhdp_update_link_status(mhdp);
if (mhdp->connector.dev) {
if (ret < 0)
- schedule_work(&mhdp->modeset_retry_work);
+ queue_work(cadence_mhdp_wq, &mhdp->modeset_retry_work);
else
drm_kms_helper_hotplug_event(mhdp->bridge.dev);
} else {
@@ -2632,7 +2634,27 @@ static struct platform_driver mhdp_driver = {
.probe = cdns_mhdp_probe,
.remove = cdns_mhdp_remove,
};
-module_platform_driver(mhdp_driver);
+
+static int __init mhdp_init(void)
+{
+ int ret;
+
+ cadence_mhdp_wq = alloc_workqueue("cadence_mhdp_wq", 0, 0);
+ if (!cadence_mhdp_wq)
+ return -ENOMEM;
+ ret = platform_driver_register(&mhdp_driver);
+ if (ret)
+ destroy_workqueue(cadence_mhdp_wq);
+ return ret;
+}
+module_init(mhdp_init);
+
+static void __exit mhdp_exit(void)
+{
+ platform_driver_unregister(&mhdp_driver);
+ destroy_workqueue(cadence_mhdp_wq);
+}
+module_exit(mhdp_exit);
MODULE_FIRMWARE(FW_NAME);
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
index bedddd510d17..e6c475612480 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
@@ -419,4 +419,6 @@ struct cdns_mhdp_device {
u32 cdns_mhdp_wait_for_sw_event(struct cdns_mhdp_device *mhdp, uint32_t event);
+extern struct workqueue_struct *cadence_mhdp_wq;
+
#endif
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c
index 946212a95598..09f9e3d42f11 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c
@@ -449,14 +449,14 @@ static int cdns_mhdp_hdcp_check_link(struct cdns_mhdp_device *mhdp)
ret = _cdns_mhdp_hdcp_disable(mhdp);
if (ret) {
mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
- schedule_work(&mhdp->hdcp.prop_work);
+ queue_work(cadence_mhdp_wq, &mhdp->hdcp.prop_work);
goto out;
}
ret = _cdns_mhdp_hdcp_enable(mhdp, mhdp->hdcp.hdcp_content_type);
if (ret) {
mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
- schedule_work(&mhdp->hdcp.prop_work);
+ queue_work(cadence_mhdp_wq, &mhdp->hdcp.prop_work);
}
out:
mutex_unlock(&mhdp->hdcp.mutex);
@@ -474,8 +474,8 @@ static void cdns_mhdp_hdcp_check_work(struct work_struct *work)
hdcp);
if (!cdns_mhdp_hdcp_check_link(mhdp))
- schedule_delayed_work(&hdcp->check_work,
- DRM_HDCP_CHECK_PERIOD_MS);
+ queue_delayed_work(cadence_mhdp_wq, &hdcp->check_work,
+ DRM_HDCP_CHECK_PERIOD_MS);
}
static void cdns_mhdp_hdcp_prop_work(struct work_struct *work)
@@ -538,9 +538,9 @@ int cdns_mhdp_hdcp_enable(struct cdns_mhdp_device *mhdp, u8 content_type)
mhdp->hdcp.hdcp_content_type = content_type;
mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_ENABLED;
- schedule_work(&mhdp->hdcp.prop_work);
- schedule_delayed_work(&mhdp->hdcp.check_work,
- DRM_HDCP_CHECK_PERIOD_MS);
+ queue_work(cadence_mhdp_wq, &mhdp->hdcp.prop_work);
+ queue_delayed_work(cadence_mhdp_wq, &mhdp->hdcp.check_work,
+ DRM_HDCP_CHECK_PERIOD_MS);
out:
mutex_unlock(&mhdp->hdcp.mutex);
return ret;
@@ -553,7 +553,7 @@ int cdns_mhdp_hdcp_disable(struct cdns_mhdp_device *mhdp)
mutex_lock(&mhdp->hdcp.mutex);
if (mhdp->hdcp.value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_UNDESIRED;
- schedule_work(&mhdp->hdcp.prop_work);
+ queue_work(cadence_mhdp_wq, &mhdp->hdcp.prop_work);
ret = _cdns_mhdp_hdcp_disable(mhdp);
}
mutex_unlock(&mhdp->hdcp.mutex);
--
2.18.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2] gpu/drm/bridge/cadence: avoid flush_scheduled_work() usage
2022-06-10 14:30 [PATCH] gpu/drm/bridge/cadence: avoid flush_scheduled_work() usage Tetsuo Handa
@ 2022-06-10 14:35 ` Tetsuo Handa
2022-06-13 13:57 ` Tetsuo Handa
0 siblings, 1 reply; 4+ messages in thread
From: Tetsuo Handa @ 2022-06-10 14:35 UTC (permalink / raw)
To: Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, David Airlie, Daniel Vetter
Cc: DRI
Use local wq in order to avoid flush_scheduled_work() usage.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
Changes in v2:
Replace flush_scheduled_work() with flush_workqueue().
Please see commit c4f135d643823a86 ("workqueue: Wrap flush_workqueue()
using a macro") for background.
This is a blind conversion, and is only compile tested.
.../drm/bridge/cadence/cdns-mhdp8546-core.c | 32 ++++++++++++++++---
.../drm/bridge/cadence/cdns-mhdp8546-core.h | 2 ++
.../drm/bridge/cadence/cdns-mhdp8546-hdcp.c | 16 +++++-----
3 files changed, 37 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
index 67f0f444b4e8..f29c9484d4bb 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -53,6 +53,8 @@
#include "cdns-mhdp8546-hdcp.h"
#include "cdns-mhdp8546-j721e.h"
+struct workqueue_struct *cadence_mhdp_wq;
+
static int cdns_mhdp_mailbox_read(struct cdns_mhdp_device *mhdp)
{
int ret, empty;
@@ -2049,7 +2051,7 @@ static void cdns_mhdp_atomic_enable(struct drm_bridge *bridge,
out:
mutex_unlock(&mhdp->link_mutex);
if (ret < 0)
- schedule_work(&mhdp->modeset_retry_work);
+ queue_work(cadence_mhdp_wq, &mhdp->modeset_retry_work);
}
static void cdns_mhdp_atomic_disable(struct drm_bridge *bridge,
@@ -2373,7 +2375,7 @@ static irqreturn_t cdns_mhdp_irq_handler(int irq, void *data)
spin_unlock(&mhdp->start_lock);
if (bridge_attached && (sw_ev0 & CDNS_DPTX_HPD)) {
- schedule_work(&mhdp->hpd_work);
+ queue_work(cadence_mhdp_wq, &mhdp->hpd_work);
}
if (sw_ev0 & ~CDNS_DPTX_HPD) {
@@ -2413,7 +2415,7 @@ static void cdns_mhdp_hpd_work(struct work_struct *work)
ret = cdns_mhdp_update_link_status(mhdp);
if (mhdp->connector.dev) {
if (ret < 0)
- schedule_work(&mhdp->modeset_retry_work);
+ queue_work(cadence_mhdp_wq, &mhdp->modeset_retry_work);
else
drm_kms_helper_hotplug_event(mhdp->bridge.dev);
} else {
@@ -2603,7 +2605,7 @@ static int cdns_mhdp_remove(struct platform_device *pdev)
pm_runtime_disable(&pdev->dev);
cancel_work_sync(&mhdp->modeset_retry_work);
- flush_scheduled_work();
+ flush_workqueue(cadence_mhdp_wq);
clk_disable_unprepare(mhdp->clk);
@@ -2632,7 +2634,27 @@ static struct platform_driver mhdp_driver = {
.probe = cdns_mhdp_probe,
.remove = cdns_mhdp_remove,
};
-module_platform_driver(mhdp_driver);
+
+static int __init mhdp_init(void)
+{
+ int ret;
+
+ cadence_mhdp_wq = alloc_workqueue("cadence_mhdp_wq", 0, 0);
+ if (!cadence_mhdp_wq)
+ return -ENOMEM;
+ ret = platform_driver_register(&mhdp_driver);
+ if (ret)
+ destroy_workqueue(cadence_mhdp_wq);
+ return ret;
+}
+module_init(mhdp_init);
+
+static void __exit mhdp_exit(void)
+{
+ platform_driver_unregister(&mhdp_driver);
+ destroy_workqueue(cadence_mhdp_wq);
+}
+module_exit(mhdp_exit);
MODULE_FIRMWARE(FW_NAME);
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
index bedddd510d17..e6c475612480 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h
@@ -419,4 +419,6 @@ struct cdns_mhdp_device {
u32 cdns_mhdp_wait_for_sw_event(struct cdns_mhdp_device *mhdp, uint32_t event);
+extern struct workqueue_struct *cadence_mhdp_wq;
+
#endif
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c
index 946212a95598..09f9e3d42f11 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c
@@ -449,14 +449,14 @@ static int cdns_mhdp_hdcp_check_link(struct cdns_mhdp_device *mhdp)
ret = _cdns_mhdp_hdcp_disable(mhdp);
if (ret) {
mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
- schedule_work(&mhdp->hdcp.prop_work);
+ queue_work(cadence_mhdp_wq, &mhdp->hdcp.prop_work);
goto out;
}
ret = _cdns_mhdp_hdcp_enable(mhdp, mhdp->hdcp.hdcp_content_type);
if (ret) {
mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
- schedule_work(&mhdp->hdcp.prop_work);
+ queue_work(cadence_mhdp_wq, &mhdp->hdcp.prop_work);
}
out:
mutex_unlock(&mhdp->hdcp.mutex);
@@ -474,8 +474,8 @@ static void cdns_mhdp_hdcp_check_work(struct work_struct *work)
hdcp);
if (!cdns_mhdp_hdcp_check_link(mhdp))
- schedule_delayed_work(&hdcp->check_work,
- DRM_HDCP_CHECK_PERIOD_MS);
+ queue_delayed_work(cadence_mhdp_wq, &hdcp->check_work,
+ DRM_HDCP_CHECK_PERIOD_MS);
}
static void cdns_mhdp_hdcp_prop_work(struct work_struct *work)
@@ -538,9 +538,9 @@ int cdns_mhdp_hdcp_enable(struct cdns_mhdp_device *mhdp, u8 content_type)
mhdp->hdcp.hdcp_content_type = content_type;
mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_ENABLED;
- schedule_work(&mhdp->hdcp.prop_work);
- schedule_delayed_work(&mhdp->hdcp.check_work,
- DRM_HDCP_CHECK_PERIOD_MS);
+ queue_work(cadence_mhdp_wq, &mhdp->hdcp.prop_work);
+ queue_delayed_work(cadence_mhdp_wq, &mhdp->hdcp.check_work,
+ DRM_HDCP_CHECK_PERIOD_MS);
out:
mutex_unlock(&mhdp->hdcp.mutex);
return ret;
@@ -553,7 +553,7 @@ int cdns_mhdp_hdcp_disable(struct cdns_mhdp_device *mhdp)
mutex_lock(&mhdp->hdcp.mutex);
if (mhdp->hdcp.value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_UNDESIRED;
- schedule_work(&mhdp->hdcp.prop_work);
+ queue_work(cadence_mhdp_wq, &mhdp->hdcp.prop_work);
ret = _cdns_mhdp_hdcp_disable(mhdp);
}
mutex_unlock(&mhdp->hdcp.mutex);
--
2.18.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] gpu/drm/bridge/cadence: avoid flush_scheduled_work() usage
2022-06-10 14:35 ` [PATCH v2] " Tetsuo Handa
@ 2022-06-13 13:57 ` Tetsuo Handa
2022-06-30 4:33 ` Tetsuo Handa
0 siblings, 1 reply; 4+ messages in thread
From: Tetsuo Handa @ 2022-06-13 13:57 UTC (permalink / raw)
To: Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, David Airlie, Daniel Vetter
Cc: DRI
On 2022/06/10 23:35, Tetsuo Handa wrote:
> Use local wq in order to avoid flush_scheduled_work() usage.
>
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> ---
> Changes in v2:
> Replace flush_scheduled_work() with flush_workqueue().
>
> Please see commit c4f135d643823a86 ("workqueue: Wrap flush_workqueue()
> using a macro") for background.
>
> This is a blind conversion, and is only compile tested.
>
> .../drm/bridge/cadence/cdns-mhdp8546-core.c | 32 ++++++++++++++++---
> .../drm/bridge/cadence/cdns-mhdp8546-core.h | 2 ++
> .../drm/bridge/cadence/cdns-mhdp8546-hdcp.c | 16 +++++-----
> 3 files changed, 37 insertions(+), 13 deletions(-)
>
I'm thinking about flush_work() version, and I got confused.
Since cdns-mhdp8546 driver uses 4 works
mhdp->modeset_retry_work
mhdp->hpd_work
mhdp->hdcp.check_work
mhdp->hdcp.prop_work
I assume that flush_scheduled_work() in cdns_mhdp_remove() needs to wait
for only these 4 works. And since mhdp->modeset_retry_work already uses
cancel_work_sync(), flush_scheduled_work() would need to wait for only 3 works.
Therefore, I guess that the flush_work() version would look something like
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
index 67f0f444b4e8..04b21752ab3f 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -2603,7 +2603,11 @@ static int cdns_mhdp_remove(struct platform_device *pdev)
pm_runtime_disable(&pdev->dev);
cancel_work_sync(&mhdp->modeset_retry_work);
- flush_scheduled_work();
+ flush_work(&mhdp->hpd_work);
+ if (mhdp->hdcp_supported) {
+ cancel_delayed_work_sync(&mhdp->hdcp.check_work);
+ flush_work(&mhdp->hdcp.prop_work);
+ }
clk_disable_unprepare(mhdp->clk);
but I came to wonder whether mhdp->hdcp.check_work should be flushed or cancelled.
While flush_scheduled_work() waits for completion of works which were already queued
to system_wq, mhdp->modeset_retry_work and mhdp->hdcp.check_work are delayed works.
That is, work won't be queued to system_wq unless timeout expires.
Current code will wait for mhdp->hdcp.check_work only if timeout already expired.
If timeout is not expired yet, flush_scheduled_work() will fail to cancel
mhdp->hdcp.check_work, and cdns_mhdp_hdcp_check_work() which is triggered by
mhdp->hdcp.check_work will schedule hdcp->check_work, which is too late for
flush_scheduled_work() to wait for completion of cdns_mhdp_hdcp_prop_work().
Thus, how do we want to handle this race window?
flush_delayed_work(&mhdp->hdcp.check_work) followed by
flush_work(&mhdp->hdcp.prop_work) (i.e. flush as much as possible) ?
cancel_delayed_work_sync(&mhdp->hdcp.check_work) followed by
cancel_work_sync(&mhdp->hdcp.prop_work) (i.e. cancel as much as possible) ?
do nothing (i.e. no need to flush or cancel mhdp->hdcp.check_work and mhdp->hdcp.prop_work) ?
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] gpu/drm/bridge/cadence: avoid flush_scheduled_work() usage
2022-06-13 13:57 ` Tetsuo Handa
@ 2022-06-30 4:33 ` Tetsuo Handa
0 siblings, 0 replies; 4+ messages in thread
From: Tetsuo Handa @ 2022-06-30 4:33 UTC (permalink / raw)
To: Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, David Airlie, Daniel Vetter
Cc: DRI
Ping?
On 2022/06/13 22:57, Tetsuo Handa wrote:
> Thus, how do we want to handle this race window?
>
> flush_delayed_work(&mhdp->hdcp.check_work) followed by
> flush_work(&mhdp->hdcp.prop_work) (i.e. flush as much as possible) ?
>
> cancel_delayed_work_sync(&mhdp->hdcp.check_work) followed by
> cancel_work_sync(&mhdp->hdcp.prop_work) (i.e. cancel as much as possible) ?
>
> do nothing (i.e. no need to flush or cancel mhdp->hdcp.check_work and mhdp->hdcp.prop_work) ?
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-06-30 4:33 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-06-10 14:30 [PATCH] gpu/drm/bridge/cadence: avoid flush_scheduled_work() usage Tetsuo Handa
2022-06-10 14:35 ` [PATCH v2] " Tetsuo Handa
2022-06-13 13:57 ` Tetsuo Handa
2022-06-30 4:33 ` Tetsuo Handa
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