From: Geert Uytterhoeven <geert@linux-m68k.org> To: Pekka Paalanen <ppaalanen@gmail.com> Cc: "Javier Martinez Canillas" <javierm@redhat.com>, "Daniel Vetter" <daniel.vetter@ffwll.ch>, "Simon Ser" <contact@emersion.fr>, "Linux PWM List" <linux-pwm@vger.kernel.org>, "Linux Fbdev development list" <linux-fbdev@vger.kernel.org>, "Noralf Trønnes" <noralf@tronnes.org>, "David Airlie" <airlied@linux.ie>, "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>, "DRI Development" <dri-devel@lists.freedesktop.org>, "Liam Girdwood" <lgirdwood@gmail.com>, "Mark Brown" <broonie@kernel.org>, "Maxime Ripard" <maxime@cerno.tech>, "Thomas Zimmermann" <tzimmermann@suse.de>, "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>, "Thierry Reding" <thierry.reding@gmail.com>, "Andy Shevchenko" <andriy.shevchenko@linux.intel.com>, "Lee Jones" <lee.jones@linaro.org> Subject: Re: [PATCH 0/4] drm/tiny: Add driver for Solomon SSD1307 OLED displays Date: Tue, 1 Feb 2022 12:07:07 +0100 [thread overview] Message-ID: <CAMuHMdX_uyEznHy5vYwS8Q=+bBKPddeJa41KTWi4Fwh3tjX+zQ@mail.gmail.com> (raw) In-Reply-To: <20220201124208.39c31e59@eldfell> Hi Pekka, On Tue, Feb 1, 2022 at 11:42 AM Pekka Paalanen <ppaalanen@gmail.com> wrote: > On Tue, 1 Feb 2022 10:49:03 +0100 > Javier Martinez Canillas <javierm@redhat.com> wrote: > > On 2/1/22 09:38, Daniel Vetter wrote: > > > On Tue, Feb 1, 2022 at 9:34 AM Simon Ser <contact@emersion.fr> wrote: > > >> On Tuesday, February 1st, 2022 at 09:26, Geert Uytterhoeven <geert@linux-m68k.org> wrote: > > >>> What's the story with the Rn formats? > > >>> > > >>> The comments say "n bpp Red", while this is a monochrome (even > > >>> inverted) display? > > >> > > >> I don't think the color matters that much. "Red" was picked just because it was > > >> an arbitrary color, to make the difference with e.g. C8. Or am I mistaken? > > > > > > The red comes from gl, where with shaders it really doesn't matter > > > what meaning you attach to channels, but really just how many you > > > have. So 2-channel formats are called RxGx, 3-channel RxGxBx, > > > 4-channel RxGxBxAx and single-channel Rx. And we use drm_fourcc for > > > interop in general, hence why these exist. > > > > > > We should probably make a comment that this really isn't a red channel > > > when used for display it's a greyscale/intensity format. Aside from > > > that documentation gap I think reusing Rx formats for > > > greyscale/intensity for display makes perfect sense. > > > -Daniel > > > > To sump up the conversation in the #dri-devel channel, these drivers > > should support the following formats: > > > > 1) Dx (Daniel suggested that for darkness, but inverted mono) > > Did you consider format C1 instead? That would be a 2-color display, which is not necessarily black and white. Cfr. Amiga or Atari bit planes with bpp=1. That's why fbdev has separate visuals for monochrome. > I have no idea how this would map to fbdev API though. #define FB_VISUAL_MONO01 0 /* Monochr. 1=Black 0=White */ #define FB_VISUAL_MONO10 1 /* Monochr. 1=White 0=Black */ #define FB_VISUAL_TRUECOLOR 2 /* True color */ The above is RGB (or grayscale, see below). #define FB_VISUAL_PSEUDOCOLOR 3 /* Pseudo color (like atari) */ Palette #define FB_VISUAL_DIRECTCOLOR 4 /* Direct color */ Usually used as RGB with gamma correction, but the actual hardware is more flexible. #define FB_VISUAL_STATIC_PSEUDOCOLOR 5 /* Pseudo color readonly */ Fixed palette And: struct fb_var_screeninfo { ... __u32 grayscale; /* 0 = color, 1 = grayscale, */ Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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From: Geert Uytterhoeven <geert@linux-m68k.org> To: Pekka Paalanen <ppaalanen@gmail.com> Cc: "Linux PWM List" <linux-pwm@vger.kernel.org>, "Linux Fbdev development list" <linux-fbdev@vger.kernel.org>, "Liam Girdwood" <lgirdwood@gmail.com>, "David Airlie" <airlied@linux.ie>, "Daniel Vetter" <daniel.vetter@ffwll.ch>, "Mark Brown" <broonie@kernel.org>, "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>, "Javier Martinez Canillas" <javierm@redhat.com>, "DRI Development" <dri-devel@lists.freedesktop.org>, "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>, "Noralf Trønnes" <noralf@tronnes.org>, "Thierry Reding" <thierry.reding@gmail.com>, "Maxime Ripard" <maxime@cerno.tech>, "Thomas Zimmermann" <tzimmermann@suse.de>, "Andy Shevchenko" <andriy.shevchenko@linux.intel.com>, "Lee Jones" <lee.jones@linaro.org> Subject: Re: [PATCH 0/4] drm/tiny: Add driver for Solomon SSD1307 OLED displays Date: Tue, 1 Feb 2022 12:07:07 +0100 [thread overview] Message-ID: <CAMuHMdX_uyEznHy5vYwS8Q=+bBKPddeJa41KTWi4Fwh3tjX+zQ@mail.gmail.com> (raw) In-Reply-To: <20220201124208.39c31e59@eldfell> Hi Pekka, On Tue, Feb 1, 2022 at 11:42 AM Pekka Paalanen <ppaalanen@gmail.com> wrote: > On Tue, 1 Feb 2022 10:49:03 +0100 > Javier Martinez Canillas <javierm@redhat.com> wrote: > > On 2/1/22 09:38, Daniel Vetter wrote: > > > On Tue, Feb 1, 2022 at 9:34 AM Simon Ser <contact@emersion.fr> wrote: > > >> On Tuesday, February 1st, 2022 at 09:26, Geert Uytterhoeven <geert@linux-m68k.org> wrote: > > >>> What's the story with the Rn formats? > > >>> > > >>> The comments say "n bpp Red", while this is a monochrome (even > > >>> inverted) display? > > >> > > >> I don't think the color matters that much. "Red" was picked just because it was > > >> an arbitrary color, to make the difference with e.g. C8. Or am I mistaken? > > > > > > The red comes from gl, where with shaders it really doesn't matter > > > what meaning you attach to channels, but really just how many you > > > have. So 2-channel formats are called RxGx, 3-channel RxGxBx, > > > 4-channel RxGxBxAx and single-channel Rx. And we use drm_fourcc for > > > interop in general, hence why these exist. > > > > > > We should probably make a comment that this really isn't a red channel > > > when used for display it's a greyscale/intensity format. Aside from > > > that documentation gap I think reusing Rx formats for > > > greyscale/intensity for display makes perfect sense. > > > -Daniel > > > > To sump up the conversation in the #dri-devel channel, these drivers > > should support the following formats: > > > > 1) Dx (Daniel suggested that for darkness, but inverted mono) > > Did you consider format C1 instead? That would be a 2-color display, which is not necessarily black and white. Cfr. Amiga or Atari bit planes with bpp=1. That's why fbdev has separate visuals for monochrome. > I have no idea how this would map to fbdev API though. #define FB_VISUAL_MONO01 0 /* Monochr. 1=Black 0=White */ #define FB_VISUAL_MONO10 1 /* Monochr. 1=White 0=Black */ #define FB_VISUAL_TRUECOLOR 2 /* True color */ The above is RGB (or grayscale, see below). #define FB_VISUAL_PSEUDOCOLOR 3 /* Pseudo color (like atari) */ Palette #define FB_VISUAL_DIRECTCOLOR 4 /* Direct color */ Usually used as RGB with gamma correction, but the actual hardware is more flexible. #define FB_VISUAL_STATIC_PSEUDOCOLOR 5 /* Pseudo color readonly */ Fixed palette And: struct fb_var_screeninfo { ... __u32 grayscale; /* 0 = color, 1 = grayscale, */ Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
next prev parent reply other threads:[~2022-02-01 11:07 UTC|newest] Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-31 20:12 [PATCH 0/4] drm/tiny: Add driver for Solomon SSD1307 OLED displays Javier Martinez Canillas 2022-01-31 20:12 ` Javier Martinez Canillas 2022-01-31 20:12 ` [PATCH 1/4] drm: Add I2C connector type Javier Martinez Canillas 2022-01-31 20:12 ` Javier Martinez Canillas 2022-01-31 20:52 ` Sam Ravnborg 2022-01-31 23:26 ` Javier Martinez Canillas 2022-01-31 23:26 ` Javier Martinez Canillas 2022-02-01 12:58 ` Noralf Trønnes 2022-02-01 12:58 ` Noralf Trønnes 2022-02-01 13:06 ` Javier Martinez Canillas 2022-02-01 13:20 ` Noralf Trønnes 2022-02-01 13:55 ` Javier Martinez Canillas 2022-02-01 13:38 ` Simon Ser 2022-02-01 13:38 ` Simon Ser 2022-02-01 14:20 ` Noralf Trønnes 2022-02-01 14:20 ` Noralf Trønnes 2022-02-01 20:57 ` Sam Ravnborg 2022-02-01 22:29 ` Simon Ser 2022-02-01 22:29 ` Simon Ser 2022-02-02 8:46 ` Javier Martinez Canillas 2022-02-02 8:46 ` Javier Martinez Canillas 2022-02-02 9:14 ` Thomas Zimmermann 2022-02-02 9:14 ` Thomas Zimmermann 2022-02-02 9:45 ` Noralf Trønnes 2022-02-02 9:45 ` Noralf Trønnes 2022-02-02 15:04 ` Pekka Paalanen 2022-02-02 15:04 ` Pekka Paalanen 2022-02-02 16:00 ` Noralf Trønnes 2022-02-02 16:00 ` Noralf Trønnes 2022-01-31 20:12 ` [PATCH 2/4] drm/format-helper: Add drm_fb_gray8_to_mono_reversed() Javier Martinez Canillas 2022-01-31 20:12 ` Javier Martinez Canillas 2022-02-01 9:59 ` Thomas Zimmermann 2022-02-01 9:59 ` Thomas Zimmermann 2022-02-01 11:13 ` Pekka Paalanen 2022-02-01 11:13 ` Pekka Paalanen 2022-02-01 11:48 ` Javier Martinez Canillas 2022-02-01 11:48 ` Javier Martinez Canillas 2022-03-14 13:40 ` Geert Uytterhoeven 2022-03-14 13:40 ` Geert Uytterhoeven 2022-03-14 14:07 ` Javier Martinez Canillas 2022-03-14 14:07 ` Javier Martinez Canillas 2022-01-31 20:36 ` [PATCH 0/4] drm/tiny: Add driver for Solomon SSD1307 OLED displays Simon Ser 2022-01-31 20:36 ` Simon Ser 2022-01-31 20:39 ` Simon Ser 2022-01-31 20:39 ` Simon Ser 2022-01-31 23:21 ` Javier Martinez Canillas 2022-01-31 23:21 ` Javier Martinez Canillas 2022-02-01 8:26 ` Geert Uytterhoeven 2022-02-01 8:26 ` Geert Uytterhoeven 2022-02-01 8:34 ` Simon Ser 2022-02-01 8:34 ` Simon Ser 2022-02-01 8:36 ` Geert Uytterhoeven 2022-02-01 8:36 ` Geert Uytterhoeven 2022-02-01 10:08 ` Thomas Zimmermann 2022-02-01 10:08 ` Thomas Zimmermann 2022-02-01 10:11 ` Simon Ser 2022-02-01 10:11 ` Simon Ser 2022-02-01 10:17 ` Thomas Zimmermann 2022-02-01 10:17 ` Thomas Zimmermann 2022-02-01 8:38 ` Daniel Vetter 2022-02-01 8:38 ` Daniel Vetter 2022-02-01 9:49 ` Javier Martinez Canillas 2022-02-01 9:49 ` Javier Martinez Canillas 2022-02-01 10:42 ` Pekka Paalanen 2022-02-01 10:42 ` Pekka Paalanen 2022-02-01 11:07 ` Geert Uytterhoeven [this message] 2022-02-01 11:07 ` Geert Uytterhoeven 2022-02-02 9:19 ` Pekka Paalanen 2022-02-02 9:19 ` Pekka Paalanen 2022-02-02 10:55 ` Geert Uytterhoeven 2022-02-02 10:55 ` Geert Uytterhoeven 2022-01-31 20:56 ` Sam Ravnborg 2022-01-31 23:37 ` Javier Martinez Canillas 2022-01-31 23:37 ` Javier Martinez Canillas 2022-02-01 9:37 ` Andy Shevchenko 2022-02-01 9:37 ` Andy Shevchenko 2022-02-01 11:31 ` Javier Martinez Canillas 2022-02-01 11:31 ` Javier Martinez Canillas 2022-02-01 11:38 ` Geert Uytterhoeven 2022-02-01 11:38 ` Geert Uytterhoeven 2022-02-01 13:09 ` Javier Martinez Canillas 2022-02-01 13:09 ` Javier Martinez Canillas 2022-02-01 14:14 ` Geert Uytterhoeven 2022-02-01 14:14 ` Geert Uytterhoeven 2022-02-01 15:03 ` Javier Martinez Canillas 2022-02-01 15:03 ` Javier Martinez Canillas 2022-02-01 20:40 ` Sam Ravnborg 2022-02-01 20:40 ` Sam Ravnborg 2022-02-02 8:38 ` Javier Martinez Canillas 2022-02-02 8:38 ` Javier Martinez Canillas 2022-02-02 11:06 ` Andy Shevchenko 2022-02-02 11:06 ` Andy Shevchenko 2022-02-02 11:39 ` Javier Martinez Canillas 2022-02-02 11:39 ` Javier Martinez Canillas 2022-02-02 11:50 ` Andy Shevchenko 2022-02-02 11:50 ` Andy Shevchenko 2022-02-02 11:54 ` Javier Martinez Canillas 2022-02-02 11:54 ` Javier Martinez Canillas 2022-02-02 12:21 ` Andy Shevchenko 2022-02-02 12:21 ` Andy Shevchenko 2022-02-01 8:43 ` Geert Uytterhoeven 2022-02-01 8:43 ` Geert Uytterhoeven 2022-02-01 9:27 ` Simon Ser 2022-02-01 9:27 ` Simon Ser 2022-02-01 10:36 ` Javier Martinez Canillas 2022-02-01 10:36 ` Javier Martinez Canillas
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