From: Javier Martinez Canillas <javierm@redhat.com>
To: Mark Brown <broonie@kernel.org>
Cc: "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
"Linux Fbdev development list" <linux-fbdev@vger.kernel.org>,
"Noralf Trønnes" <noralf@tronnes.org>,
"Sam Ravnborg" <sam@ravnborg.org>,
"Linux PWM List" <linux-pwm@vger.kernel.org>,
"David Airlie" <airlied@linux.ie>,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"DRI Development" <dri-devel@lists.freedesktop.org>,
"Liam Girdwood" <lgirdwood@gmail.com>,
"Rob Herring" <robh+dt@kernel.org>,
"Geert Uytterhoeven" <geert@linux-m68k.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 v2 0/4] drm/tiny: Add driver for Solomon SSD1307 OLED displays
Date: Tue, 8 Feb 2022 16:32:10 +0100 [thread overview]
Message-ID: <10e06ad6-e8bd-a6de-3334-c682125e7753@redhat.com> (raw)
In-Reply-To: <YgKJtjoFMSzxNiiI@sirena.org.uk>
Hello Mark,
On 2/8/22 16:18, Mark Brown wrote:
> On Tue, Feb 08, 2022 at 04:10:49PM +0100, Javier Martinez Canillas wrote:
>> On 2/8/22 15:19, Geert Uytterhoeven wrote:
>
>>> - "time ls" on the serial console (no files in the current directory,
>>> so nothing to print) increases from 0.86s to 1.92s, so the system is
>>> more loaded. As ssd1307fb relied on deferred I/O too, the slowdown
>>> might be (partly) due to redrawing of the visual artefacts
>>> mentioned above.
>
>> I was trying to first have the driver and then figure out how to optimize
>> it. For v3 I'm using regmap to access instead of the I2C layer directly.
>
>> I noticed that this is even slower but it makes the driver more clean and
>> allows to support both I2C and SPI (untested but will include it as a WIP).
>
> I wouldn't have expected regmap to add huge overhead relative to I2C,
> partly predicated on I2C being rather slow itself. There will be some
> overhead for concurrency protection and data marshalling but for I2C
> clocked at normal speeds it's surprising.
Thanks for chiming in. That's good to know, I'll investigate more then.
Probably I was wrongly blaming regmap while it was another change that
is causing the display to be refreshed at a slower rate than before.
Best regards,
--
Javier Martinez Canillas
Linux Engineering
Red Hat
next prev parent reply other threads:[~2022-02-08 15:32 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-04 13:43 [PATCH v2 0/4] drm/tiny: Add driver for Solomon SSD1307 OLED displays Javier Martinez Canillas
2022-02-04 13:43 ` [PATCH v2 1/4] drm/format-helper: Add drm_fb_{xrgb8888,gray8}_to_mono_reversed() Javier Martinez Canillas
2022-02-04 15:52 ` Thomas Zimmermann
2022-02-04 16:00 ` Thomas Zimmermann
2022-02-04 19:31 ` Javier Martinez Canillas
2022-02-04 20:35 ` Thomas Zimmermann
2022-02-04 21:02 ` Ilia Mirkin
2022-02-07 12:44 ` [PATCH v2 1/4] drm/format-helper: Add drm_fb_{xrgb8888, gray8}_to_mono_reversed() Thomas Zimmermann
2022-02-04 13:43 ` [PATCH v2 2/4] drm/tiny: Add driver for Solomon SSD130X OLED displays Javier Martinez Canillas
2022-02-04 14:26 ` Andy Shevchenko
2022-02-04 19:19 ` Javier Martinez Canillas
2022-02-05 13:04 ` Andy Shevchenko
2022-02-05 17:40 ` Javier Martinez Canillas
2022-02-04 13:43 ` [PATCH v2 3/4] MAINTAINERS: Add entry for Solomon SSD130X OLED displays DRM driver Javier Martinez Canillas
2022-02-04 13:57 ` Andy Shevchenko
2022-02-04 14:12 ` Javier Martinez Canillas
2022-02-04 14:28 ` Andy Shevchenko
2022-02-04 14:33 ` Javier Martinez Canillas
2022-02-04 13:43 ` [PATCH v2 4/4] dt-bindings: display: ssd1307fb: Add myself as binding co-maintainer Javier Martinez Canillas
2022-02-09 22:14 ` Rob Herring
2022-02-04 14:31 ` [PATCH v2 0/4] drm/tiny: Add driver for Solomon SSD1307 OLED displays Geert Uytterhoeven
2022-02-04 14:37 ` Javier Martinez Canillas
2022-02-08 14:19 ` Geert Uytterhoeven
2022-02-08 15:10 ` Javier Martinez Canillas
2022-02-08 15:18 ` Mark Brown
2022-02-08 15:32 ` Javier Martinez Canillas [this message]
2022-02-08 15:23 ` Geert Uytterhoeven
2022-02-08 15:40 ` Javier Martinez Canillas
2022-02-08 17:19 ` Javier Martinez Canillas
2022-02-09 13:47 ` Andy Shevchenko
2022-02-09 14:27 ` Geert Uytterhoeven
2022-02-09 14:42 ` Javier Martinez Canillas
2022-02-09 15:32 ` Andy Shevchenko
2022-02-10 8:32 ` Maxime Ripard
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