linux-kernel - [RFC][PATCH 0/2] Export platform_pci_set_power

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Date:	Mon, 23 Mar 2009 22:30:09 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Jesse Barnes <jbarnes@...tuousgeek.org>
Cc:	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Linux PCI <linux-pci@...r.kernel.org>,
	pm list <linux-pm@...ts.linux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: [RFC][PATCH 0/2] Export platform_pci_set_power_state() and make radeonfb use it

On Sunday 22 March 2009, Rafael J. Wysocki wrote:
> On Saturday 21 March 2009, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rjw@...k.pl>
> > 
> > The story in http://bugzilla.kernel.org/show_bug.cgi?id=12846 shows
> > that setting the power state of a PCI device by
> > pci_raw_set_power_state() may sometimes fail.  For this reason,
> > pci_raw_set_power_state() should not assume that the power state of
> > the device has actually changed after writing into its PMCSR.
> > Instead, it should read the value from there and use it to update
> > dev->current_state.  It also is useful to print a warning if the
> > device's power state hasn't changed as expected.
> > 
> > Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
> > ---
> OK, since the Ben's radeonfb fix for bug #12846 has been merged, I'd like
> to do something a bit different.
> 
> Patch 1/2 introduces __pci_set_power_state() that will allow the radeonfb
> driver not to open code PCI PM operations.
> 
> Patch 2/2 makes the driver use __pci_set_power_state().
> 
> Comments welcome.

Well, Jesse doesn't like these patches very much, so here's an alternative.

1/2 changes platform_pci_set_power_state() into an exported function (and uses
it to simplify pci_set_power_state() a bit) so that the radeonfb driver can use
it.

2/2 modifies the radeonfb driver itself.

Thanks,
Rafael

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