Re: [PATCH] Logitech G13 driver (fixed cc list --- ignore others)

From: Jaya Kumar <jayakumar.lkml@gmail.com>
To: "Rick L. Vinyard Jr." <rvinyard@cs.nmsu.edu>
Cc: linux-kernel@vger.kernel.org, krzysztof.h1@wp.pl,
	akpm@linux-foundation.org, linux-usb@vger.kernel.org,
	oliver@neukum.org, linux-input@vger.kernel.org, jkosina@suse.cz
Subject: Re: [PATCH] Logitech G13 driver (fixed cc list --- ignore others)
Date: Tue, 5 Jan 2010 07:57:44 +0800	[thread overview]
Message-ID: <45a44e481001041557t1f87f8d4i959abbbee0c4346@mail.gmail.com> (raw)
In-Reply-To: <200912142122.nBELMW7d001243@mustang.cs.nmsu.edu>

On Tue, Dec 15, 2009 at 5:22 AM, Rick L. Vinyard Jr.
<rvinyard@cs.nmsu.edu> wrote:
> Additionally, this device contains a 160x43 monochrome LCD display.
> A registered framebuffer device manages this display. The design
> of this portion of the driver was based on the design of the
> hecubafb driver with deferred framebuffer I/O since there is
> no real memory to map.

Hi Rick,

Interesting work. I recommend CCing linux-fbdev@vger.kernel.org too
since it contains a fbdev interface.

> +config LOGITECH_G13
> +       tristate "Logitech G13 gameboard support"
> +       depends on HID_LOGITECH
> +       depends on FB
> +       select FB_SYS_FILLRECT
> +       select FB_SYS_COPYAREA
> +       select FB_SYS_IMAGEBLIT
> +       select FB_SYS_FOPS

Does this need to select FB_DEFERRED_IO?

> --- /dev/null
> +++ b/drivers/hid/hid-g13-logo.xbm
> @@ -0,0 +1,75 @@
> +#define g13_lcd_width 160
> +#define g13_lcd_height 43
> +static unsigned char g13_lcd_bits[] = {
> +   0x00, 0x00, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

Was there a reason for having a new logo file? If so, you might want
to put it in the comments and also put it together with the standard
kernel logo.

> +/* 160*43 rounded to nearest whole byte which is 160*48 since bytes are
> +   vertical the y component must be a multiple of 8 */
> +#define G13FB_SIZE (160*48/8)

Minor nit, I think there is a macro for this, DIV_ROUND_UP, or maybe
this could be better done in the function that uses this value.

> +static ssize_t g13_set_mled(struct hid_device *hdev, unsigned mled);

Does this need to be here or can the code be reordered?

> +static struct fb_var_screeninfo g13fb_var = {
> +       .xres = G13FB_WIDTH,
> +       .yres = G13FB_HEIGHT,
> +       .xres_virtual = G13FB_WIDTH,
> +       .yres_virtual = G13FB_HEIGHT,
> +       .bits_per_pixel = 1,
> +       .nonstd = 1,
> +};

I think the nonstd is a bug. Yes, hecubafb and metronomefb seem to
have the same bug as well. nonstd is used if you want something like
FB_NONSTD_HAM or FB_NONSTD_REV_PIX_IN_B, which I don't think is what
you want.

Hope this helps.

Best regards,
jaya