linux-kernel - [PATCH 1/2] x86/mrst/pci: assign d3

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Date:	Wed, 08 Feb 2012 14:52:35 +0000
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] x86/mrst/pci: assign d3_delay to 0 for

From: Jacob Pan <jacob.jun.pan@...ux.intel.com>

Langwell devices are not true pci devices, they are not subject to the 10 ms
d3 to d0 delay required by pci spec. This patch assigns d3_delay to 0 for all
langwell pci devices.

We can also power off devices that are not really used by the OS

Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Signed-off-by: Alan Cox <alan@...ux.intel.com>
---

 arch/x86/pci/mrst.c |   24 ++++++++++++++++++++++++
 1 files changed, 24 insertions(+), 0 deletions(-)


diff --git a/arch/x86/pci/mrst.c b/arch/x86/pci/mrst.c
index cb29191..89e5548 100644
--- a/arch/x86/pci/mrst.c
+++ b/arch/x86/pci/mrst.c
@@ -239,6 +239,30 @@ int __init pci_mrst_init(void)
 	return 1;
 }
 
+/* Langwell devices are not true pci devices, they are not subject to 10 ms
+ * d3 to d0 delay required by pci spec.
+ */
+static void __devinit pci_d3delay_fixup(struct pci_dev *dev)
+{
+	/* true pci devices in lincroft should allow type 1 access, the rest
+	 * are langwell fake pci devices.
+	 */
+	if (type1_access_ok(dev->bus->number, dev->devfn, PCI_DEVICE_ID))
+		return;
+	dev->d3_delay = 0;
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_d3delay_fixup);
+
+static void __devinit mrst_power_off_unused_dev(struct pci_dev *dev)
+{
+	pci_set_power_state(dev, PCI_D3cold);
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0801, mrst_power_off_unused_dev);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0809, mrst_power_off_unused_dev);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x080C, mrst_power_off_unused_dev);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0812, mrst_power_off_unused_dev);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0815, mrst_power_off_unused_dev);
+
 /*
  * Langwell devices reside at fixed offsets, don't try to move them.
  */

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