linux-kernel - Re: [PATCH 2/7] video: fbdev: intelfb: delete double assignment

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Date:	Tue, 26 Aug 2014 13:56:13 +0300
From:	Tomi Valkeinen <tomi.valkeinen@...com>
To:	Julia Lawall <Julia.Lawall@...6.fr>,
	Maik Broemme <mbroemme@...sserver.de>
CC:	<joe@...ches.com>, <kernel-janitors@...r.kernel.org>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	<linux-fbdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/7] video: fbdev: intelfb: delete double assignment

On 23/08/14 21:33, Julia Lawall wrote:
> From: Julia Lawall <Julia.Lawall@...6.fr>
> 
> Delete successive assignments to the same location.
> 
> In the second case, = is converted to |=, which looks appropriate based on
> the values involved.
> 
> A simplified version of the semantic match that finds this problem is as
> follows: (http://coccinelle.lip6.fr/)
> 
> // <smpl>
> @@
> expression i;
> @@
> 
> *i = ...;
>  i = ...;
> // </smpl>
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@...6.fr>
> 
> ---
> The patches in this series do not depend on each other.
> 
> This changes the behavior of the code in the second case and is not tested.

In this patch, as in the sis one, the behavior is changed. The subject
might perhaps be "fix cursor initialization"?

The patch does look like it could cause a regression, though. Anyone
able to test this?

 Tomi

> 
>  drivers/video/fbdev/intelfb/intelfbhw.c |    3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/video/fbdev/intelfb/intelfbhw.c b/drivers/video/fbdev/intelfb/intelfbhw.c
> index fbad61d..d31ed4e 100644
> --- a/drivers/video/fbdev/intelfb/intelfbhw.c
> +++ b/drivers/video/fbdev/intelfb/intelfbhw.c
> @@ -1191,7 +1191,6 @@ int intelfbhw_mode_to_hw(struct intelfb_info *dinfo,
>  	vsync_end = vsync_start + var->vsync_len;
>  	vtotal = vsync_end + var->upper_margin;
>  	vblank_start = vactive;
> -	vblank_end = vtotal;
>  	vblank_end = vsync_end + 1;
>  
>  	DBG_MSG("V: act %d, ss %d, se %d, tot %d bs %d, be %d\n",
> @@ -1859,7 +1858,7 @@ void intelfbhw_cursor_init(struct intelfb_info *dinfo)
>  		tmp = INREG(CURSOR_CONTROL);
>  		tmp &= ~(CURSOR_FORMAT_MASK | CURSOR_GAMMA_ENABLE |
>  			 CURSOR_ENABLE | CURSOR_STRIDE_MASK);
> -		tmp = CURSOR_FORMAT_3C;
> +		tmp |= CURSOR_FORMAT_3C;
>  		OUTREG(CURSOR_CONTROL, tmp);
>  		OUTREG(CURSOR_A_BASEADDR, dinfo->cursor.offset << 12);
>  		tmp = (64 << CURSOR_SIZE_H_SHIFT) |
> 



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