linux-kernel - [PATCH 1/3] atyfb: Properly save PCI state before changing PCI PM level

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Date:	Thu, 05 Feb 2009 12:06:50 +1100
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	fbdev list <linux-fbdev-devel@...ts.sourceforge.net>
CC:	"Rafael J. Wysocki" <rjw@...k.pl>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH 1/3] atyfb: Properly save PCI state before changing PCI PM level

This fixes atyfb to properly save the PCI config space -before- it
potentially switches the PM state of the chip. This avoids a
warning with the new PM core and is the right thing to do anyway.

I also slightly cleaned up the code that checks whether we are
running on a PowerMac to do a runtime check instead of a compile
check only, and replaced a deprecated number with the proper
symbolic constant.

Finally, I removed the useless switch to D0 from resume since
the core does it for us.

Signed-off-by: Benjamin Herrenschmidt <benh@...nel.crashing.org>
---

 drivers/video/aty/atyfb_base.c |   20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

--- linux-work.orig/drivers/video/aty/atyfb_base.c	2009-02-04 13:10:22.000000000 +1100
+++ linux-work/drivers/video/aty/atyfb_base.c	2009-02-04 13:13:11.000000000 +1100
@@ -1978,7 +1978,7 @@ static int aty_power_mgmt(int sleep, str
 
 	return timeout ? 0 : -EIO;
 }
-#endif
+#endif /* CONFIG_PPC_PMAC */
 
 static int atyfb_pci_suspend(struct pci_dev *pdev, pm_message_t state)
 {
@@ -2002,9 +2002,15 @@ static int atyfb_pci_suspend(struct pci_
 	par->asleep = 1;
 	par->lock_blank = 1;
 
+	/* Because we may change PCI D state ourselves, we need to
+	 * first save the config space content so the core can
+	 * restore it properly on resume.
+	 */
+	pci_save_state(pdev);
+
 #ifdef CONFIG_PPC_PMAC
 	/* Set chip to "suspend" mode */
-	if (aty_power_mgmt(1, par)) {
+	if (machine_is(powermac) && aty_power_mgmt(1, par)) {
 		par->asleep = 0;
 		par->lock_blank = 0;
 		atyfb_blank(FB_BLANK_UNBLANK, info);
@@ -2047,11 +2053,15 @@ static int atyfb_pci_resume(struct pci_d
 
 	acquire_console_sem();
 
+	/* PCI state will have been restored by the core, so
+	 * we should be in D0 now with our config space fully
+	 * restored
+	 */
+
 #ifdef CONFIG_PPC_PMAC
-	if (pdev->dev.power.power_state.event == 2)
+	if (machine_is(powermac) &&
+	    pdev->dev.power.power_state.event == PM_EVENT_SUSPEND)
 		aty_power_mgmt(0, par);
-#else
-	pci_set_power_state(pdev, PCI_D0);
 #endif
 
 	aty_resume_chip(info);
--
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