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

From: Thomas Zimmermann <tzimmermann@suse.de>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: freedreno@lists.freedesktop.org,
	linux-samsung-soc@vger.kernel.org, amd-gfx@lists.freedesktop.org,
	linux-arm-msm@vger.kernel.org, intel-gfx@lists.freedesktop.org,
	javierm@redhat.com, dri-devel@lists.freedesktop.org,
	linux-tegra@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 01/10] drm/client: Test for connectors before sending hotplug event
Date: Fri, 27 Jan 2023 15:13:50 +0100	[thread overview]
Message-ID: <bf1aa950-3b58-3e33-4849-2ee7fbefcfcc@suse.de> (raw)
In-Reply-To: <Y9GWfi4EiCDPa6BJ@ravnborg.org>

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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

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

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