Date:	Tue, 22 Jun 2010 12:34:09 -0600
From:	"Rick L. Vinyard, Jr." <rvinyard@...nmsu.edu>
To:	"Jiri Kosina" <jkosina@...e.cz>
Cc:	"Marek Vasut" <marek.vasut@...il.com>,
	"Pavel Machek" <pavel@....cz>,
	"Jaya Kumar" <jayakumar.lkml@...il.com>,
	linux-kernel@...r.kernel.org, felipe.balbi@...ia.com,
	linux-usb@...r.kernel.org, oliver@...kum.org,
	linux-input@...r.kernel.org, dmitry.torokhov@...il.com,
	npavel@...ner.com, tomi.valkeinen@...ia.com, tony@...mide.com,
	florianschandinat@....de, krzysztof.h1@...pl,
	akpm@...ux-foundation.org, linux-fbdev@...r.kernel.org,
	bonbons@...ux-vserver.org
Subject: Re: [PATCH] hid Logitech G13 Driver 0.0.5


Jiri Kosina wrote:
> On Sat, 19 Jun 2010, Marek Vasut wrote:
>
>> > > >> +/*
>> > > >> + * This is a default logo to be loaded upon driver
>> initialization
>> > > >> + * replacing the default Logitech G13 image loaded on device
>> > > >> + * initialization. This is to provide the user a cue that the
>> > > >> + * Linux driver is loaded and ready.
>> > > >> + *
>> > > >> + * This logo contains the text G13 in the center with two
>> penguins
>> > > >> + * on each side of the text. The penguins are a 33x40 rendition
>> of
>> > > >> + * the default framebuffer 80x80 monochrome image scaled down
>> and
>> > > >> + * cleaned up to retain something that looks a little better
>> than
>> > > >> + * a simple scaling.
>> > > >> + *
>> > > >> + * This logo is a simple xbm image created in GIMP and exported.
>> > > >> + * To view the image copy the following two #defines plus the
>> > > >> + * g13_lcd_bits to an ASCII text file and save with extension
>> > > >> + * .xbm, then open with GIMP or any other graphical editor
>> > > >> + * such as eog that recognizes the .xbm format.
>> > > >> + */
>> > > >
>> > > > ...
>> > > >
>> > > >> +static unsigned char g13_lcd_bits[] = {
>> > > >> + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
>> 0x00,
>> > > >> 0x00,
>> > > >
>> > > > I think you'll agree above is not an elegant solution.
>> > >
>> > > I could make it a config option.
>> >
>> > You get about 10 complains already, but you are not willing to solve
>> > it. No, config option does not help.
>> >
>> > If you want to, make it separate patch so we can reject it separately.
>> >
>> > > >> +static DEVICE_ATTR(rgb, 0666, g13_rgb_show, g13_rgb_store);
>> > > >
>> > > > Reading above code, it looks like this new userspace sysfs
>> attribute
>> > > > is for backlight control. Could that be better exposed using the
>> > > > existing backlight class?
>> > >
>> > > I looked at the backlight class and it didn't seem to be a very good
>> fit.
>> > >
>> > > /* This structure defines all the properties of a backlight */
>> > > struct backlight_properties {
>> > >
>> > > 	/* Current User requested brightness (0 - max_brightness) */
>> > > 	int brightness;
>> > > 	/* Maximal value for brightness (read-only) */
>> > > 	int max_brightness;
>> > > 	/* Current FB Power mode (0: full on, 1..3: power saving
>> > >
>> > > 	   modes; 4: full off), see FB_BLANK_XXX */
>> > >
>> > > 	int power;
>> > > 	/* FB Blanking active? (values as for power) */
>> > > 	/* Due to be removed, please use (state & BL_CORE_FBBLANK) */
>> > > 	int fb_blank;
>> > > 	/* Flags used to signal drivers of state changes */
>> > > 	/* Upper 4 bits are reserved for driver internal use */
>> > > 	unsigned int state;
>> > >
>> > > };
>> > >
>> > > The g13's backlight doesn't support any of these properties. All you
>> can
>> > > set is an rgb value on the g13; no power modes, no brightness, etc.
>> I
>> > > could add a brightness attribute by scaling the rgb values, but I
>> would
>> > > prefer to do that from userspace rather than the driver since it's
>> not
>> > > supported in the device itself.
>> > >
>> > > And, we'd still have to have the rgb attribute since the backlight
>> class
>> > > doesn't have color.
>> >
>> > Or you could pretend you have 3 different backlights? ....which is
>> > actually what you have...?
>> > 									Pavel
>>
>> Any updates on this?
>>
>> btw. it'd be good if we could use the g13fb on G15 ... would that be
>> possible?
>> Cheers!
>
> Rick, please correct me if I am wrong, but as far as I remember, you have
> gathered quite some feedback and were about to incorporate them and
> re-submit the driver, which hasn't happened yet. Is that correct? Or have
> I lost track completely?
>

I've been waiting to resubmit until I get some of the userspace libraries
and utilities a little more mature. There were some things I was exposing
to sysfs that I didn't absolutely need, and some others that I needed to
add.

The cairo and papyrus libraries are (preliminarily) fully working. Once I
make sure I have everything the daemon will need I'll resubmit the driver,
and once that is done I was planning on submitting the libs/utils to
Fedora.

For now, I've been dropping Fedora 12/13 patches and kernel SRPMS here:
http://miskatonic.cs.nmsu.edu/g13/

And the userspace libraries/utilities are at:
http://g13.sourceforge.net

As for the g13fb on the G15... I would imagine it could be done, but I
don't have a G15 so I can't say for sure.

If I had to guess I think you'll have to take the core functionality of
the keyboard driver and extend it with the fb code in the _same_ driver if
the keyboard and display use a similar design to the G13.

The G13 uses the same endpoint for both keyboard input and display
messages, and since a USB endpoint can't be shared across drivers both
will have to reside in the same driver.

--

Rick

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