linux-kernel - Re: [PATCH RESEND] video: w100fb: Reduce sleep mode battery discharge

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Message-ID: <4FE78582.5080503@gmx.de>
Date:	Sun, 24 Jun 2012 21:24:18 +0000
From:	Florian Tobias Schandinat <FlorianSchandinat@....de>
To:	Paul Parsons <lost.distance@...oo.com>
CC:	mreimer@...systems.com, philipp.zabel@...il.com,
	linux-kernel@...r.kernel.org,
	"linux-fbdev@...r.kernel.org" <linux-fbdev@...r.kernel.org>
Subject: Re: [PATCH RESEND] video: w100fb: Reduce sleep mode battery discharge

Hi Paul,

you should als the relevant mailing list, linux-fbdev (done now)

On 06/03/2012 10:33 AM, Paul Parsons wrote:
> In 2006 and 2007 the handhelds.org kernel w100fb driver was patched to
> reduce sleep mode battery discharge. Unfortunately those two patches
> never migrated to the mainline kernel.
> 
> Fortunately the function affected - w100_suspend() - has not changed
> since; thus those patches still apply cleanly.
> 
> Applying those patches to linux-3.4-rc3 running on an HP iPAQ hx4700
> reduces the sleep mode battery discharge from approximately 26 mA to
> approximately 11 mA.
> 
> This patch combines those two patches into a single unified patch.
> 
> Signed-off-by: Paul Parsons <lost.distance@...oo.com>
> Cc: Matt Reimer <mreimer@...systems.com>
> Cc: Philipp Zabel <philipp.zabel@...il.com>

Actually it would be good if we had the Signed-offs of the original
authors. Oh well, I think if it can't be helped yours should be sufficient.

> ---
> 
> Many thanks to Matt Reimer for suggesting this.
> 
> The seeming demise of handhelds.org has removed any formal patch logs.
> However the patches can still be viewed online:
> 2006 patch:
> http://paste.lisp.org/display/31700
> 2007 patch:
> http://osdir.com/ml/handhelds.linux.kernel/2007-02/msg00020.html
> 
> And the fully patched handhelds.org kernel is still available, e.g.:
> http://www.linuxtogo.org/~goxboxlive/htcuniversal/Kernel/linux-2.6.21-hh20.tar.bz2
> 
>  drivers/video/w100fb.c |   12 ++++++++++++
>  1 files changed, 12 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/video/w100fb.c b/drivers/video/w100fb.c
> index 90a2e30..2f6b2b8 100644
> --- a/drivers/video/w100fb.c
> +++ b/drivers/video/w100fb.c
> @@ -1567,6 +1567,18 @@ static void w100_suspend(u32 mode)
>  		val = readl(remapped_regs + mmPLL_CNTL);
>  		val |= 0x00000004;  /* bit2=1 */
>  		writel(val, remapped_regs + mmPLL_CNTL);
> +
> +		writel(0x00000000, remapped_regs + mmLCDD_CNTL1);
> +		writel(0x00000000, remapped_regs + mmLCDD_CNTL2);
> +		writel(0x00000000, remapped_regs + mmGENLCD_CNTL1);
> +		writel(0x00000000, remapped_regs + mmGENLCD_CNTL2);
> +		writel(0x00000000, remapped_regs + mmGENLCD_CNTL3);
> +
> +		val = readl(remapped_regs + mmMEM_EXT_CNTL);
> +		val |= 0xF0000000;
> +		val &= ~(0x00000001);
> +		writel(val, remapped_regs + mmMEM_EXT_CNTL);
> +

If anyone understands what this change does (like for example disabling
the LCD controller) a comment would be useful.

>  		writel(0x0000001d, remapped_regs + mmPWRMGT_CNTL);
>  	}
>  }

If nobody comments on this I will apply it in a few days.


Best regards,

Florian Tobias Schandinat
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