Re: [PATCH 06/57] fbdev: sh_mobile_hdmi: Don't access LCDC channel in notifier callback

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Guennadi,

On Wednesday 14 December 2011 00:02:11 Guennadi Liakhovetski wrote:
> On Tue, 13 Dec 2011, Laurent Pinchart wrote:
> > Instead of relying on info->par being a pointer to an LCDC channel, cast
> > the notifier block pointer to an sh_hdmi pointer.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > ---
> > 
> >  drivers/video/sh_mobile_hdmi.c |    6 +++---
> >  1 files changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/video/sh_mobile_hdmi.c
> > b/drivers/video/sh_mobile_hdmi.c index 647ba98..b1e90f5 100644
> > --- a/drivers/video/sh_mobile_hdmi.c
> > +++ b/drivers/video/sh_mobile_hdmi.c
> > @@ -225,6 +225,8 @@ struct sh_hdmi {
> > 
> >  	struct notifier_block notifier;
> >  
> >  };
> > 
> > +#define notifier_to_hdmi(n)	container_of(n, struct sh_hdmi, notifier)
> > +
> > 
> >  static void hdmi_write(struct sh_hdmi *hdmi, u8 data, u8 reg)
> >  {
> >  
> >  	iowrite8(data, hdmi->base + reg);
> > 
> > @@ -1204,9 +1206,7 @@ static int sh_hdmi_notify(struct notifier_block
> > *nb,
> > 
> >  {
> >  
> >  	struct fb_event *event = data;
> >  	struct fb_info *info = event->info;
> > 
> > -	struct sh_mobile_lcdc_chan *ch = info->par;
> > -	struct sh_mobile_lcdc_board_cfg	*board_cfg = &ch->cfg.board_cfg;
> > -	struct sh_hdmi *hdmi = board_cfg->board_data;
> > +	struct sh_hdmi *hdmi = notifier_to_hdmi(nb);
> > 
> >  	if (!hdmi || nb != &hdmi->notifier || hdmi->info != info)
> 
> Then you also can drop the first two of the three checks above. If I'm not
> mistaken, in a HDMI / LCD set up, if this notifier is called for the LCD
> panel, hdmi will wtill point to the HDMI-related sh_hdmi object, whose
> ->info will then mismatch the info pointer, derived from the notifier
> "data" pointer.

That's correct. The first two checks don't hurt, but will always be false. 
I'll remove them.

> >  		return NOTIFY_DONE;

-- 
Regards,

Laurent Pinchart