* [PATCH] drm/connector: demote connector force-probes for non-master clients
@ 2021-04-02 11:22 Simon Ser
2021-04-07 7:02 ` Pekka Paalanen
2021-04-20 9:14 ` Daniel Vetter
0 siblings, 2 replies; 7+ messages in thread
From: Simon Ser @ 2021-04-02 11:22 UTC (permalink / raw)
To: dri-devel
Force-probing a connector can be slow and cause flickering. As this
affects the global KMS state, let's make it so only the DRM master
can force-probe a connector.
Non-master DRM clients won't be able to force-probe a connector
anymore. Instead, KMS will perform a regular read-only connector
query.
Signed-off-by: Simon Ser <contact@emersion.fr>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Pekka Paalanen <ppaalanen@gmail.com>
---
drivers/gpu/drm/drm_connector.c | 11 ++++++++---
include/uapi/drm/drm_mode.h | 7 ++++---
2 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 7631f76e7f34..2f70a52a892b 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -20,6 +20,7 @@
* OF THIS SOFTWARE.
*/
+#include <drm/drm_auth.h>
#include <drm/drm_connector.h>
#include <drm/drm_edid.h>
#include <drm/drm_encoder.h>
@@ -2374,9 +2375,13 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
mutex_lock(&dev->mode_config.mutex);
if (out_resp->count_modes == 0) {
- connector->funcs->fill_modes(connector,
- dev->mode_config.max_width,
- dev->mode_config.max_height);
+ if (drm_is_current_master(file_priv))
+ connector->funcs->fill_modes(connector,
+ dev->mode_config.max_width,
+ dev->mode_config.max_height);
+ else
+ drm_dbg_kms(dev, "User-space requested a forced probe on [CONNECTOR:%d:%s] but is not the DRM master, demoting to read-only probe",
+ connector->base.id, connector->name);
}
out_resp->mm_width = connector->display_info.width_mm;
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index a5e76aa06ad5..3efa2e38d89b 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -413,9 +413,10 @@ enum drm_mode_subconnector {
*
* **Force-probing a connector**
*
- * If the @count_modes field is set to zero, the kernel will perform a forced
- * probe on the connector to refresh the connector status, modes and EDID.
- * A forced-probe can be slow, might cause flickering and the ioctl will block.
+ * If the @count_modes field is set to zero and the DRM client is the DRM
+ * master, the kernel will perform a forced probe on the connector to refresh
+ * the connector status, modes and EDID. A forced-probe can be slow, might
+ * cause flickering and the ioctl will block.
*
* User-space needs to force-probe connectors to ensure their metadata is
* up-to-date at startup and after receiving a hot-plug event. User-space
--
2.31.1
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^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] drm/connector: demote connector force-probes for non-master clients
2021-04-02 11:22 [PATCH] drm/connector: demote connector force-probes for non-master clients Simon Ser
@ 2021-04-07 7:02 ` Pekka Paalanen
2021-04-07 7:16 ` Simon Ser
2021-04-20 9:14 ` Daniel Vetter
1 sibling, 1 reply; 7+ messages in thread
From: Pekka Paalanen @ 2021-04-07 7:02 UTC (permalink / raw)
To: Simon Ser; +Cc: dri-devel
[-- Attachment #1.1: Type: text/plain, Size: 3055 bytes --]
On Fri, 2 Apr 2021 13:22:12 +0200
Simon Ser <contact@emersion.fr> wrote:
> Force-probing a connector can be slow and cause flickering. As this
> affects the global KMS state, let's make it so only the DRM master
> can force-probe a connector.
>
> Non-master DRM clients won't be able to force-probe a connector
> anymore. Instead, KMS will perform a regular read-only connector
> query.
>
> Signed-off-by: Simon Ser <contact@emersion.fr>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Pekka Paalanen <ppaalanen@gmail.com>
Hi,
seems like a good idea to me.
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Btw. can force-probe be triggered via sysfs as well and does it require
root privs?
Thanks,
pq
> ---
> drivers/gpu/drm/drm_connector.c | 11 ++++++++---
> include/uapi/drm/drm_mode.h | 7 ++++---
> 2 files changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index 7631f76e7f34..2f70a52a892b 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -20,6 +20,7 @@
> * OF THIS SOFTWARE.
> */
>
> +#include <drm/drm_auth.h>
> #include <drm/drm_connector.h>
> #include <drm/drm_edid.h>
> #include <drm/drm_encoder.h>
> @@ -2374,9 +2375,13 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
>
> mutex_lock(&dev->mode_config.mutex);
> if (out_resp->count_modes == 0) {
> - connector->funcs->fill_modes(connector,
> - dev->mode_config.max_width,
> - dev->mode_config.max_height);
> + if (drm_is_current_master(file_priv))
> + connector->funcs->fill_modes(connector,
> + dev->mode_config.max_width,
> + dev->mode_config.max_height);
> + else
> + drm_dbg_kms(dev, "User-space requested a forced probe on [CONNECTOR:%d:%s] but is not the DRM master, demoting to read-only probe",
> + connector->base.id, connector->name);
> }
>
> out_resp->mm_width = connector->display_info.width_mm;
> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> index a5e76aa06ad5..3efa2e38d89b 100644
> --- a/include/uapi/drm/drm_mode.h
> +++ b/include/uapi/drm/drm_mode.h
> @@ -413,9 +413,10 @@ enum drm_mode_subconnector {
> *
> * **Force-probing a connector**
> *
> - * If the @count_modes field is set to zero, the kernel will perform a forced
> - * probe on the connector to refresh the connector status, modes and EDID.
> - * A forced-probe can be slow, might cause flickering and the ioctl will block.
> + * If the @count_modes field is set to zero and the DRM client is the DRM
> + * master, the kernel will perform a forced probe on the connector to refresh
> + * the connector status, modes and EDID. A forced-probe can be slow, might
> + * cause flickering and the ioctl will block.
> *
> * User-space needs to force-probe connectors to ensure their metadata is
> * up-to-date at startup and after receiving a hot-plug event. User-space
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] drm/connector: demote connector force-probes for non-master clients
2021-04-07 7:02 ` Pekka Paalanen
@ 2021-04-07 7:16 ` Simon Ser
2021-04-07 7:38 ` Pekka Paalanen
0 siblings, 1 reply; 7+ messages in thread
From: Simon Ser @ 2021-04-07 7:16 UTC (permalink / raw)
To: Pekka Paalanen; +Cc: dri-devel
On Wednesday, April 7th, 2021 at 9:02 AM, Pekka Paalanen <ppaalanen@gmail.com> wrote:
> Btw. can force-probe be triggered via sysfs as well and does it require
> root privs?
sysfs can force-probe like so:
echo detect | sudo tee /sys/class/drm/card0-DP-1/status
But this requires root, yes.
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] drm/connector: demote connector force-probes for non-master clients
2021-04-07 7:16 ` Simon Ser
@ 2021-04-07 7:38 ` Pekka Paalanen
2021-04-20 8:47 ` Simon Ser
0 siblings, 1 reply; 7+ messages in thread
From: Pekka Paalanen @ 2021-04-07 7:38 UTC (permalink / raw)
To: Simon Ser; +Cc: dri-devel
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On Wed, 07 Apr 2021 07:16:30 +0000
Simon Ser <contact@emersion.fr> wrote:
> On Wednesday, April 7th, 2021 at 9:02 AM, Pekka Paalanen <ppaalanen@gmail.com> wrote:
>
> > Btw. can force-probe be triggered via sysfs as well and does it require
> > root privs?
>
> sysfs can force-probe like so:
>
> echo detect | sudo tee /sys/class/drm/card0-DP-1/status
>
> But this requires root, yes.
Ah, all good then.
Thanks,
pq
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] drm/connector: demote connector force-probes for non-master clients
2021-04-07 7:38 ` Pekka Paalanen
@ 2021-04-20 8:47 ` Simon Ser
0 siblings, 0 replies; 7+ messages in thread
From: Simon Ser @ 2021-04-20 8:47 UTC (permalink / raw)
To: Daniel Vetter; +Cc: dri-devel
Ping Daniel Vetter
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] drm/connector: demote connector force-probes for non-master clients
2021-04-02 11:22 [PATCH] drm/connector: demote connector force-probes for non-master clients Simon Ser
2021-04-07 7:02 ` Pekka Paalanen
@ 2021-04-20 9:14 ` Daniel Vetter
2021-04-20 16:53 ` Simon Ser
1 sibling, 1 reply; 7+ messages in thread
From: Daniel Vetter @ 2021-04-20 9:14 UTC (permalink / raw)
To: Simon Ser; +Cc: dri-devel
On Fri, Apr 02, 2021 at 01:22:12PM +0200, Simon Ser wrote:
> Force-probing a connector can be slow and cause flickering. As this
> affects the global KMS state, let's make it so only the DRM master
> can force-probe a connector.
>
> Non-master DRM clients won't be able to force-probe a connector
> anymore. Instead, KMS will perform a regular read-only connector
> query.
>
> Signed-off-by: Simon Ser <contact@emersion.fr>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Pekka Paalanen <ppaalanen@gmail.com>
> ---
> drivers/gpu/drm/drm_connector.c | 11 ++++++++---
> include/uapi/drm/drm_mode.h | 7 ++++---
> 2 files changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index 7631f76e7f34..2f70a52a892b 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -20,6 +20,7 @@
> * OF THIS SOFTWARE.
> */
>
> +#include <drm/drm_auth.h>
> #include <drm/drm_connector.h>
> #include <drm/drm_edid.h>
> #include <drm/drm_encoder.h>
> @@ -2374,9 +2375,13 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
>
> mutex_lock(&dev->mode_config.mutex);
> if (out_resp->count_modes == 0) {
> - connector->funcs->fill_modes(connector,
> - dev->mode_config.max_width,
> - dev->mode_config.max_height);
> + if (drm_is_current_master(file_priv))
> + connector->funcs->fill_modes(connector,
> + dev->mode_config.max_width,
> + dev->mode_config.max_height);
> + else
> + drm_dbg_kms(dev, "User-space requested a forced probe on [CONNECTOR:%d:%s] but is not the DRM master, demoting to read-only probe",
> + connector->base.id, connector->name);
> }
>
> out_resp->mm_width = connector->display_info.width_mm;
> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> index a5e76aa06ad5..3efa2e38d89b 100644
> --- a/include/uapi/drm/drm_mode.h
> +++ b/include/uapi/drm/drm_mode.h
> @@ -413,9 +413,10 @@ enum drm_mode_subconnector {
> *
> * **Force-probing a connector**
> *
> - * If the @count_modes field is set to zero, the kernel will perform a forced
> - * probe on the connector to refresh the connector status, modes and EDID.
> - * A forced-probe can be slow, might cause flickering and the ioctl will block.
> + * If the @count_modes field is set to zero and the DRM client is the DRM
*current* DRM master
The drm master/client relationship survives a DROPMASTER ioctl, but also
it's only really relevant for the old authmagic dance. But just to be
consistent here.
> + * master, the kernel will perform a forced probe on the connector to refresh
> + * the connector status, modes and EDID. A forced-probe can be slow, might
> + * cause flickering and the ioctl will block.
Do we have an igt for this? Timing test should do the job I think,
assuming we have at least one output which requires an edid read (so maybe
skip the test if a forced probe takes less than 10ms or so).
Patch lgtm, but igt would be really nice here.
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> *
> * User-space needs to force-probe connectors to ensure their metadata is
> * up-to-date at startup and after receiving a hot-plug event. User-space
> --
> 2.31.1
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] drm/connector: demote connector force-probes for non-master clients
2021-04-20 9:14 ` Daniel Vetter
@ 2021-04-20 16:53 ` Simon Ser
0 siblings, 0 replies; 7+ messages in thread
From: Simon Ser @ 2021-04-20 16:53 UTC (permalink / raw)
To: Daniel Vetter; +Cc: dri-devel
On Tuesday, April 20th, 2021 at 11:14 AM, Daniel Vetter <daniel@ffwll.ch> wrote:
> Do we have an igt for this? Timing test should do the job I think,
> assuming we have at least one output which requires an edid read (so maybe
> skip the test if a forced probe takes less than 10ms or so).
Err, an igt that only relies on timings? Sorry, but that sounds like a
recipe for flaky tests.
Ideally a chamelium test would allow to make sure all of this works as
expected. I don't really have this hw anymore though.
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^ permalink raw reply [flat|nested] 7+ messages in thread
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2021-04-02 11:22 [PATCH] drm/connector: demote connector force-probes for non-master clients Simon Ser
2021-04-07 7:02 ` Pekka Paalanen
2021-04-07 7:16 ` Simon Ser
2021-04-07 7:38 ` Pekka Paalanen
2021-04-20 8:47 ` Simon Ser
2021-04-20 9:14 ` Daniel Vetter
2021-04-20 16:53 ` Simon Ser
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