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Date:   Wed, 2 Feb 2022 12:39:29 +0100
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Subject: Re: [PATCH 0/4] drm/tiny: Add driver for Solomon SSD1307 OLED
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To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     Sam Ravnborg <sam@ravnborg.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux PWM List <linux-pwm@vger.kernel.org>,
        Linux Fbdev development list <linux-fbdev@vger.kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Mark Brown <broonie@kernel.org>,
        DRI Development <dri-devel@lists.freedesktop.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        =?UTF-8?Q?Noralf_Tr=c3=b8nnes?= <noralf@tronnes.org>,
        Maxime Ripard <maxime@cerno.tech>,
        =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= <u.kleine-koenig@pengutronix.de>,
        Thierry Reding <thierry.reding@gmail.com>,
        Lee Jones <lee.jones@linaro.org>,
        Peter Robinson <pbrobinson@gmail.com>
References: <20220131201225.2324984-1-javierm@redhat.com>
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From:   Javier Martinez Canillas <javierm@redhat.com>
In-Reply-To: <YfploeCM6C5y3Imj@smile.fi.intel.com>
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Hello Andy,

On 2/2/22 12:06, Andy Shevchenko wrote:
> On Wed, Feb 02, 2022 at 09:38:51AM +0100, Javier Martinez Canillas wrote:
>> On 2/1/22 21:40, Sam Ravnborg wrote:
> 
> ...
> 
>> Peter Robinson suggested to
>> make the driver mutually exclusive and add !FB_SSD1307 in the config symbol.
> 
> And how will distros choose "the right" option in this case?

It depends on the distro. In Fedora we are disabling *all* the fbdev drivers.

> What to do when I wan to see a regression and I want to change drivers w/o
> recompilation?
>

If you want to have the two drivers without recompilation (and same compatible
to match) then how would kmod / udev choose which one to load ? It becomes a
race condition between the two drivers which one probes first.
 
> NAK from me to that proposal.
> 

What's your suggestion then to solve the issue mentioned above ? With my distro
maintainer hat I don't care that much, since the fbdev drivers will be disabled.

Best regards,
-- 
Javier Martinez Canillas
Linux Engineering
Red Hat