linux-kernel - Re: [PATCH 05/11] video/aperture: Only kick vgacon when the pdev is decoding vga

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Message-ID: <87119376-2813-f155-a2e1-006ffa382f12@suse.de>
Date:   Wed, 11 Jan 2023 17:03:02 +0100
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     Daniel Vetter <daniel.vetter@...ll.ch>,
        DRI Development <dri-devel@...ts.freedesktop.org>
Cc:     linux-fbdev@...r.kernel.org,
        Intel Graphics Development <intel-gfx@...ts.freedesktop.org>,
        Javier Martinez Canillas <javierm@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Daniel Vetter <daniel.vetter@...el.com>,
        Helge Deller <deller@....de>
Subject: Re: [PATCH 05/11] video/aperture: Only kick vgacon when the pdev is
 decoding vga

Hi

Am 11.01.23 um 16:41 schrieb Daniel Vetter:
> Otherwise it's bit silly, and we might throw out the driver for the
> screen the user is actually looking at. I haven't found a bug report
> for this case yet, but we did get bug reports for the analog case
> where we're throwing out the efifb driver.
> 
> References: https://bugzilla.kernel.org/show_bug.cgi?id=216303
> Signed-off-by: Daniel Vetter <daniel.vetter@...el.com>
> Cc: Thomas Zimmermann <tzimmermann@...e.de>
> Cc: Javier Martinez Canillas <javierm@...hat.com>
> Cc: Helge Deller <deller@....de>
> Cc: linux-fbdev@...r.kernel.org
> ---
>   drivers/video/aperture.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/video/aperture.c b/drivers/video/aperture.c
> index 3d8c925c7365..6f351a58f6c6 100644
> --- a/drivers/video/aperture.c
> +++ b/drivers/video/aperture.c
> @@ -341,6 +341,9 @@ int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *na
>   			return ret;
>   	}
>   
> +	if (!primary)
> +		return 0;
> +

The original code from fbdev didn't do this, so this code didn't either.

It appears more to be a special case than an early-out branch. So can we 
write it as

if (primary) {
   // kick_vgacon
}

?

Best regards
Thomas

>   	/*
>   	 * WARNING: Apparently we must kick fbdev drivers before vgacon,
>   	 * otherwise the vga fbdev driver falls over.

-- 
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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