Subject: Re: [PATCH] radeonfb: (#2)  Implement proper workarounds for PLL
	accesses
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Andreas Schwab <schwab@suse.de>
Cc: Andrew Morton <akpm@osdl.org>, Linus Torvalds <torvalds@osdl.org>,
       Linux Kernel list <linux-kernel@vger.kernel.org>
In-Reply-To: <jeoecr1qk8.fsf@sykes.suse.de>
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Date: Thu, 07 Apr 2005 08:47:35 +1000
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On Thu, 2005-04-07 at 00:35 +0200, Andreas Schwab wrote:
> Benjamin Herrenschmidt <benh@kernel.crashing.org> writes:
> 
> > Hrm... it should only add a few ms, maybe about 20 ms to the mode
> > switching... If you remove the radeon_msleep(5) call from the
> > radeon_pll_errata_after_data() routine in radeonfb.h, does it make a
> > difference ?
> 
> Yes, it does.  Without the sleep, switching is as fast as before.

It is weird tho. Could you try adding a printk or something to figure
out how much this is called during a typical swich ? It will seriously
spam your console though ... I would expect only 5 or 6 calls during a
normal switch (since the PLL value shouldn't change for a flat panel),
that is no more than maybe 50ms, while it seems you are having a much
bigger delay.

Ben.

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