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[v3,01/10] drm/client: Test for connectors before sending hotplug event

Message ID 20230125200415.14123-2-tzimmermann@suse.de
State Superseded
Headers show
Series drm/fb-helper: Various cleanups | expand

Commit Message

Thomas Zimmermann Jan. 25, 2023, 8:04 p.m. UTC
Test for connectors in the client code and remove a similar test
from the generic fbdev emulation. Do nothing if the test fails.
Not having connectors indicates a driver bug.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/gpu/drm/drm_client.c        | 5 +++++
 drivers/gpu/drm/drm_fbdev_generic.c | 5 -----
 2 files changed, 5 insertions(+), 5 deletions(-)

Comments

Thomas Zimmermann Jan. 27, 2023, 2:13 p.m. UTC | #1
Hi

Am 25.01.23 um 21:52 schrieb Sam Ravnborg:
> Hi Thomas,
> 
> On Wed, Jan 25, 2023 at 09:04:06PM +0100, Thomas Zimmermann wrote:
>> Test for connectors in the client code and remove a similar test
>> from the generic fbdev emulation. Do nothing if the test fails.
>> Not having connectors indicates a driver bug.
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
>> ---
>>   drivers/gpu/drm/drm_client.c        | 5 +++++
>>   drivers/gpu/drm/drm_fbdev_generic.c | 5 -----
>>   2 files changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c
>> index 262ec64d4397..09ac191c202d 100644
>> --- a/drivers/gpu/drm/drm_client.c
>> +++ b/drivers/gpu/drm/drm_client.c
>> @@ -198,6 +198,11 @@ void drm_client_dev_hotplug(struct drm_device *dev)
>>   	if (!drm_core_check_feature(dev, DRIVER_MODESET))
>>   		return;
>>   
>> +	if (!dev->mode_config.num_connector) {
>> +		drm_dbg_kms(dev, "No connectors found, will not send hotplug events!\n");
>> +		return;
> This deserves a more visible logging - if a driver fails here it would
> be good to spot it in the normal kernel log.
> drm_info or drm_notice?

But is that really noteworthy? AFAIK, this situation can legally happen. 
So if it's expected, why should we print a message about it?

Best regards
Thomas

> 
> The original code had this on the debug level, but when moving the log
> level could also be updated.
> 
> 	Sam
> 
>> +	}
>> +
>>   	mutex_lock(&dev->clientlist_mutex);
>>   	list_for_each_entry(client, &dev->clientlist, list) {
>>   		if (!client->funcs || !client->funcs->hotplug)
>> diff --git a/drivers/gpu/drm/drm_fbdev_generic.c b/drivers/gpu/drm/drm_fbdev_generic.c
>> index 0a4c160e0e58..3d455a2e3fb5 100644
>> --- a/drivers/gpu/drm/drm_fbdev_generic.c
>> +++ b/drivers/gpu/drm/drm_fbdev_generic.c
>> @@ -389,11 +389,6 @@ static int drm_fbdev_client_hotplug(struct drm_client_dev *client)
>>   	if (dev->fb_helper)
>>   		return drm_fb_helper_hotplug_event(dev->fb_helper);
>>   
>> -	if (!dev->mode_config.num_connector) {
>> -		drm_dbg_kms(dev, "No connectors found, will not create framebuffer!\n");
>> -		return 0;
>> -	}
>> -
>>   	drm_fb_helper_prepare(dev, fb_helper, &drm_fb_helper_generic_funcs);
>>   
>>   	ret = drm_fb_helper_init(dev, fb_helper);
>> -- 
>> 2.39.0
Sam Ravnborg Jan. 27, 2023, 5:33 p.m. UTC | #2
On Fri, Jan 27, 2023 at 03:13:50PM +0100, Thomas Zimmermann wrote:
> Hi
> 
> Am 25.01.23 um 21:52 schrieb Sam Ravnborg:
> > Hi Thomas,
> > 
> > On Wed, Jan 25, 2023 at 09:04:06PM +0100, Thomas Zimmermann wrote:
> > > Test for connectors in the client code and remove a similar test
> > > from the generic fbdev emulation. Do nothing if the test fails.
> > > Not having connectors indicates a driver bug.
> > > 
> > > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> > > Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
> > > ---
> > >   drivers/gpu/drm/drm_client.c        | 5 +++++
> > >   drivers/gpu/drm/drm_fbdev_generic.c | 5 -----
> > >   2 files changed, 5 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c
> > > index 262ec64d4397..09ac191c202d 100644
> > > --- a/drivers/gpu/drm/drm_client.c
> > > +++ b/drivers/gpu/drm/drm_client.c
> > > @@ -198,6 +198,11 @@ void drm_client_dev_hotplug(struct drm_device *dev)
> > >   	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> > >   		return;
> > > +	if (!dev->mode_config.num_connector) {
> > > +		drm_dbg_kms(dev, "No connectors found, will not send hotplug events!\n");
> > > +		return;
> > This deserves a more visible logging - if a driver fails here it would
> > be good to spot it in the normal kernel log.
> > drm_info or drm_notice?
> 
> But is that really noteworthy? AFAIK, this situation can legally happen. So
> if it's expected, why should we print a message about it?
I was reading it as a driver error - as that's not the case current code
is fine.

	Sam
Simon Ser Jan. 27, 2023, 6:02 p.m. UTC | #3
On Wednesday, January 25th, 2023 at 21:04, Thomas Zimmermann <tzimmermann@suse.de> wrote:

> Not having connectors indicates a driver bug.

Is it? What if all connectors are of the DP-MST type, ie. they are
created on-the-fly?
Thomas Zimmermann Jan. 30, 2023, 8:40 a.m. UTC | #4
Hi

Am 27.01.23 um 19:02 schrieb Simon Ser:
> On Wednesday, January 25th, 2023 at 21:04, Thomas Zimmermann <tzimmermann@suse.de> wrote:
> 
>> Not having connectors indicates a driver bug.
> 
> Is it? What if all connectors are of the DP-MST type, ie. they are
> created on-the-fly?

My commit message was nonsense. I even write this here that having no 
connectors is legitimate.

Best regards
Thomas
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c
index 262ec64d4397..09ac191c202d 100644
--- a/drivers/gpu/drm/drm_client.c
+++ b/drivers/gpu/drm/drm_client.c
@@ -198,6 +198,11 @@  void drm_client_dev_hotplug(struct drm_device *dev)
 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
 		return;
 
+	if (!dev->mode_config.num_connector) {
+		drm_dbg_kms(dev, "No connectors found, will not send hotplug events!\n");
+		return;
+	}
+
 	mutex_lock(&dev->clientlist_mutex);
 	list_for_each_entry(client, &dev->clientlist, list) {
 		if (!client->funcs || !client->funcs->hotplug)
diff --git a/drivers/gpu/drm/drm_fbdev_generic.c b/drivers/gpu/drm/drm_fbdev_generic.c
index 0a4c160e0e58..3d455a2e3fb5 100644
--- a/drivers/gpu/drm/drm_fbdev_generic.c
+++ b/drivers/gpu/drm/drm_fbdev_generic.c
@@ -389,11 +389,6 @@  static int drm_fbdev_client_hotplug(struct drm_client_dev *client)
 	if (dev->fb_helper)
 		return drm_fb_helper_hotplug_event(dev->fb_helper);
 
-	if (!dev->mode_config.num_connector) {
-		drm_dbg_kms(dev, "No connectors found, will not create framebuffer!\n");
-		return 0;
-	}
-
 	drm_fb_helper_prepare(dev, fb_helper, &drm_fb_helper_generic_funcs);
 
 	ret = drm_fb_helper_init(dev, fb_helper);