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Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display

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Den 29.07.2017 21.40, skrev David Lechner:
> On 07/29/2017 02:17 PM, David Lechner wrote:
>> The goal of this series is to get the built-in LCD of the LEGO 
>> MINDSTORMS EV3
>> working. But, most of the content here is building up the 
>> infrastructure to do
>> that.
>>
>
> Some general comments/questions:
>
> I have noticed that DRM doesn't really have support for monochrome 
> displays. I'm guessing that is because no one really uses them anymore?
>

The repaper driver was the first monochrome drm driver and I chose to
present it to userspace as XRGB8888 and convert it to monochrome.
The reason for this is that everything, libraries, apps, plymouth (boot
splash, no rgb565) supports it. I didn't see any point in adding a new
monochrome drm format that didn't have, or probably wouldn't get
userspace support (by libraries at least). The application of course
needs to know this to get a good result.

tinydrm_xrgb8888_to_gray8() does the conversion:
https://cgit.freedesktop.org/drm/drm-misc/commit/drivers/gpu/drm/tinydrm?id=379ea9a1a59a5a32c8db6f164e80a3fd00cb3781

> The LEGO EV3 display is just an LCD (not the backlit kind). It has two 
> modes of operation. It can to 2bbp grayscale or it can do 1bpp 
> monochrome. The grayscale isn't the best (looks splotchy in places), 
> so it would be nice to be able to choose between these two modes. How 
> would I implement something like that?
>

Do you expect anyone to use grayscale if it doesn't look good?
Maybe better to add it later if there's a demand for it.

> Also, how can I indicate to userspace that this display really is 
> monochrome/grayscale since the reported color depth 16bpp?
>

There isn't unless we add formats for it.
Since this display is in a Lego piece, doesn't it have custom userspace
that already know it's monochrome?

Noralf.

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[PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display David Lechner <david@lechnology.com> - 2017-07-29 21:20 +0200
  [PATCH 4/6] drm/tinydrm: mipi-panel: refactor to use driver id David Lechner <david@lechnology.com> - 2017-07-29 21:20 +0200
    Re: [PATCH 4/6] drm/tinydrm: mipi-panel: refactor to use driver id Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-07-30 20:30 +0200
  [PATCH 5/6] drm/tinydrm: add support for LEGO MINDSTORMS EV3 LCD David Lechner <david@lechnology.com> - 2017-07-29 21:20 +0200
    Re: [PATCH 5/6] drm/tinydrm: add support for LEGO MINDSTORMS EV3 LCD Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-07-30 20:30 +0200
  [PATCH 3/6] drm/tinydrm: rename mi028qt module to mipi-panel David Lechner <david@lechnology.com> - 2017-07-29 21:20 +0200
    Re: [PATCH 3/6] drm/tinydrm: rename mi028qt module to mipi-panel David Lechner <david@lechnology.com> - 2017-07-29 21:40 +0200
  [PATCH 6/6] ARM: dts: da850-lego-ev3: Add node for LCD display David Lechner <david@lechnology.com> - 2017-07-29 21:20 +0200
  [PATCH 2/6] drm/tinydrm: add helpers for ST7586 controllers David Lechner <david@lechnology.com> - 2017-07-29 21:20 +0200
    Re: [PATCH 2/6] drm/tinydrm: add helpers for ST7586 controllers Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-07-30 20:20 +0200
  Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display David Lechner <david@lechnology.com> - 2017-07-29 21:50 +0200
    Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display Noralf Trønnes <noralf@tronnes.org> - 2017-07-30 19:20 +0200
      Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display David Lechner <david@lechnology.com> - 2017-08-01 19:00 +0200
        Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display Noralf Trønnes <noralf@tronnes.org> - 2017-08-01 20:10 +0200
          Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display David Lechner <david@lechnology.com> - 2017-08-02 00:30 +0200
            Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display Noralf Trønnes <noralf@tronnes.org> - 2017-08-02 10:10 +0200
              Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display David Lechner <david@lechnology.com> - 2017-08-02 18:10 +0200
                Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display Daniel Vetter <daniel@ffwll.ch> - 2017-08-03 12:10 +0200
            Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display Noralf Trønnes <noralf@tronnes.org> - 2017-08-03 16:10 +0200
              Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display David Lechner <david@lechnology.com> - 2017-08-03 17:20 +0200
                Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-08-03 19:10 +0200
                Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-08-03 19:20 +0200
                Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display Noralf Trønnes <noralf@tronnes.org> - 2017-08-03 22:20 +0200
                Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display David Lechner <david@lechnology.com> - 2017-08-04 03:10 +0200
                Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display David Lechner <david@lechnology.com> - 2017-08-04 03:20 +0200
  Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display Noralf Trønnes <noralf@tronnes.org> - 2017-07-30 19:20 +0200
  Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-07-30 20:30 +0200
    Re: [PATCH 0/6] Support for LEGO MINDSTORMS EV3 LCD display Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-07-30 20:30 +0200

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