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

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:

quoted

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

quoted

+	}
+
  	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

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev