From: David Lechner <david@lechnology.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org, Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: [PATCH v5] drm/fb-helper: pass physical dimensions to fbdev
Date: Sat, 5 Aug 2017 10:57:50 -0500 [thread overview]
Message-ID: <3ac80a0e-707c-6bf9-4e19-d3a455303ff4@lechnology.com> (raw)
In-Reply-To: <5131811.ZCEmYft6Yc@avalon>
On 08/04/2017 04:53 PM, Laurent Pinchart wrote:
> Hi David,
>
> Thank you for the patch.
>
> On Friday 04 Aug 2017 11:25:24 David Lechner wrote:
>> The fbdev subsystem has a place for physical dimensions (width and height
>> in mm) that is readable by userspace. Since DRM also knows these
>> dimensions, pass this information to the fbdev device.
>
> I'm curious, what's your use case for this ? What userspace software do you
> use that is still based on fbdev and needs screen dimensions ?
I have dug up an old graphics library called GRX[1] and modernized
it[2]. So, I am using the screen dimensions to make it DPI-aware so that
the font on my 2.4" screen looks the same size as my 2.8" screen when
both are 320x240 pixels. Until this year, all of the displays I have
only have fbdev drivers.
[1]: http://grx.gnu.de
[2]: https://github.com/ev3dev/grx
next prev parent reply other threads:[~2017-08-05 15:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-04 16:25 [PATCH v5] drm/fb-helper: pass physical dimensions to fbdev David Lechner
2017-08-04 21:53 ` Laurent Pinchart
2017-08-05 15:57 ` David Lechner [this message]
2017-08-07 9:43 ` Daniel Vetter
2017-08-07 13:40 ` David Lechner
2017-08-07 15:01 ` Daniel Vetter
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