linux-kernel - Re: [PATCH]: Fix radeon blanking return value.

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Date:	Thu, 01 Mar 2007 09:56:50 +0800
From:	"Antonino A. Daplas" <adaplas@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH]: Fix radeon blanking return value.

On Wed, 2007-02-28 at 16:20 -0800, David Miller wrote:
> If you'll recall, over a year ago, I pointed out that the current
> Radeon driver erroneously returns -EINVAL for valid blanking codes,
> here is a link to that thread:
> 
> 	http://lkml.org/lkml/2006/1/28/6
> 
> No other driver does this, and it confuses the X server into thinking
> that the device does not support blanking properly.
> 
> As a result I have to switch to a console VC and back to the X server
> to unblank the screen, which is rediculious.
> 
> I've had to do this for more than 3 years and I'm really tired of this
> problem still being around :-)
> 
> I looked again and there is simply no reason for the Radeon driver to
> return -EINVAL for FB_BLANK_NORMAL.  It claims it wants to do this in
> order to convince fbcon to blank in software, right here:
> 
> 			if (fb_blank(info, blank))
> 				fbcon_generic_blank(vc, info, blank);
> 
> to software blank the screen.  But it only causes that to happen
> in the FB_BLANK_NORMAL case.
> 
> That makes no sense because the Radeon code does this:
> 
> 		val |= CRTC_DISPLAY_DIS;
> 
> in the FB_BLANK_NORMAL case so should be blanking the hardware, and
> there is therefore no reason to SW blank by returning -EINVAL.
> 
> Therefore I propose we finally apply the following patch.  No other
> fbdev driver does this madness, and as I've shown above there is no
> justification for the behavior at all :-)

This was before radeonfb did not fully differentiate each blanking
levels.  Currently, it is fixed, so I agree with this patch.

> 
> Signed-off-by: David S. Miller <davem@...emloft.net>
Acked-by: Antonino Daplas <adaplas@...il.com>

Tony


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