From: Javier Martinez Canillas <javierm@redhat.com>
To: Thomas Zimmermann <tzimmermann@suse.de>,
lee@kernel.org, daniel.thompson@linaro.org, jingoohan1@gmail.com,
deller@gmx.de
Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
linux-input@vger.kernel.org, linux-pwm@vger.kernel.org
Subject: Re: [PATCH 01/10] backlight: Match backlight device against struct fb_info.bl_dev
Date: Tue, 20 Feb 2024 10:46:21 +0100 [thread overview]
Message-ID: <87edd7ii36.fsf@minerva.mail-host-address-is-not-set> (raw)
In-Reply-To: <a5b9a2d8-f305-4b68-9086-76d5f1b985c7@suse.de>
Thomas Zimmermann <tzimmermann@suse.de> writes:
> Hi
>
> Am 20.02.24 um 10:17 schrieb Javier Martinez Canillas:
>> Thomas Zimmermann <tzimmermann@suse.de> writes:
>>
>> Hello Thomas,
>>
>>> Framebuffer drivers for devices with dedicated backlight are supposed
>>> to set struct fb_info.bl_dev to the backlight's respective device. Use
>>> the value to match backlight and framebuffer in the backlight core code.
>>>
>>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>>> ---
>>> drivers/video/backlight/backlight.c | 9 +++++++--
>>> 1 file changed, 7 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
>>> index 86e1cdc8e3697..48844a4f28ad3 100644
>>> --- a/drivers/video/backlight/backlight.c
>>> +++ b/drivers/video/backlight/backlight.c
>>> @@ -98,7 +98,8 @@ static int fb_notifier_callback(struct notifier_block *self,
>>> {
>>> struct backlight_device *bd;
>>> struct fb_event *evdata = data;
>>> - int node = evdata->info->node;
>>> + struct fb_info *info = evdata->info;
>>> + int node = info->node;
>>> int fb_blank = 0;
>>>
>>> /* If we aren't interested in this event, skip it immediately ... */
>>> @@ -110,8 +111,12 @@ static int fb_notifier_callback(struct notifier_block *self,
>>>
>>> if (!bd->ops)
>>> goto out;
>>> - if (bd->ops->check_fb && !bd->ops->check_fb(bd, evdata->info))
>>> + else if (bd->ops->check_fb && !bd->ops->check_fb(bd, info))
>>> goto out;
>>> +#if IS_ENABLED(CONFIG_FB_BACKLIGHT)
>>> + else if (info->bl_dev && info->bl_dev != bd)
>> If the driver doesn't provide a struct backlight_ops .check_fb callback, I
>> think that having an info->bl_dev should be mandatory ? Or at least maybe
>> there should be a warning if info->bl_dev isn't set ?
>
> bl_dev can only be used for display drivers that set an explicit
> backlight device; otherwise it's NULL. There seem to be systems where
> backlight and display are distinct. And the docs for check_fb say that
> by default the backlight matches against any display. I tried to keep
> this semantics by silently succeeding if neither check_fb nor bl_dev
> have bene set.
>
>>
>> The would be a driver bug, right ?
>
> I assume that some systems create the backlight instance from platform
> data or DT and the display driver has no means of knowing about it.
>
Ok. I thought that in that case a (platform specific) .check_fb callback
would have to be provided then. But if the semantic is that none could be
missing, then I guess is OK to silently succeeding.
I wonder if at least a debug printout is worth it. But maybe a follow-up.
> Best regards
> Thomas
>
--
Best regards,
Javier Martinez Canillas
Core Platforms
Red Hat
next prev parent reply other threads:[~2024-02-20 9:46 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-12 16:16 [PATCH 00/10] backlight: Replace struct fb_info in interfaces Thomas Zimmermann
2024-02-12 16:16 ` [PATCH 01/10] backlight: Match backlight device against struct fb_info.bl_dev Thomas Zimmermann
2024-02-15 12:02 ` Daniel Thompson
2024-02-20 9:17 ` Javier Martinez Canillas
2024-02-20 9:37 ` Thomas Zimmermann
2024-02-20 9:46 ` Javier Martinez Canillas [this message]
2024-02-12 16:16 ` [PATCH 02/10] auxdisplay/ht16k33: Remove struct backlight_ops.check_fb Thomas Zimmermann
2024-02-13 13:17 ` Robin van der Gracht
2024-02-20 9:18 ` Javier Martinez Canillas
2024-02-12 16:16 ` [PATCH 03/10] hid/hid-picolcd: Fix initialization order Thomas Zimmermann
2024-02-20 9:19 ` Javier Martinez Canillas
2024-02-12 16:16 ` [PATCH 04/10] hid/hid-picolcd: Remove struct backlight_ops.check_fb Thomas Zimmermann
2024-02-13 14:53 ` kernel test robot
2024-02-13 21:57 ` kernel test robot
2024-02-15 12:06 ` Daniel Thompson
2024-02-15 12:19 ` Thomas Zimmermann
2024-02-20 9:24 ` Javier Martinez Canillas
2024-02-12 16:16 ` [PATCH 05/10] backlight/aat2870-backlight: Remove struct backlight.check_fb Thomas Zimmermann
2024-02-15 12:06 ` Daniel Thompson
2024-02-20 9:26 ` Javier Martinez Canillas
2024-02-12 16:16 ` [PATCH 06/10] backlight/pwm-backlight: Remove struct backlight_ops.check_fb Thomas Zimmermann
2024-02-12 17:25 ` Uwe Kleine-König
2024-02-15 12:08 ` Daniel Thompson
2024-02-20 9:27 ` Javier Martinez Canillas
2024-02-12 16:16 ` [PATCH 07/10] fbdev/sh_mobile_lcdc_fb: " Thomas Zimmermann
2024-02-20 9:27 ` Javier Martinez Canillas
2024-02-12 16:16 ` [PATCH 08/10] fbdev/ssd1307fb: Init backlight before registering framebuffer Thomas Zimmermann
2024-02-20 9:32 ` Javier Martinez Canillas
2024-02-12 16:16 ` [PATCH 09/10] fbdev/ssd1307fb: Remove struct backlight_ops.check_fb Thomas Zimmermann
2024-02-20 9:32 ` Javier Martinez Canillas
2024-02-12 16:16 ` [PATCH 10/10] backlight: Add controls_device callback to struct backlight_ops Thomas Zimmermann
2024-02-15 12:09 ` Daniel Thompson
2024-02-20 9:35 ` Javier Martinez Canillas
2024-02-15 12:13 ` [PATCH 00/10] backlight: Replace struct fb_info in interfaces Daniel Thompson
2024-02-15 12:23 ` Thomas Zimmermann
2024-02-19 15:02 ` Lee Jones
2024-02-21 9:23 ` Thomas Zimmermann
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