RE: [PATCH v6] Quirk for IVB graphics FLR errata

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For IvyBridge Mobile platform, a system hang may occur if a FLR(Function Level Reset) is asserted to internal graphics.

This quirk patch is workaround for the IVB FLR errata issue.
We are disabling the FLR reset handshake between the PCH and CPU display, then
manually powering down the panel power sequencing and resetting the PCH display.

Signed-off-by: Xudong Hao <xudong.hao@xxxxxxxxx>
Signed-off-by: Kay, Allen M <allen.m.kay@xxxxxxxxx>
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
---
 drivers/pci/quirks.c |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 48 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 4bf7102..213cad9 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -29,6 +29,7 @@
 #include <linux/sched.h>
 #include <linux/ktime.h>
 #include <asm/dma.h>	/* isa_dma_bridge_buggy */
+#include <asm/io.h>
 #include "pci.h"
 
 /*
@@ -3085,11 +3086,58 @@ static int reset_intel_82599_sfp_virtfn(struct pci_dev *dev, int probe)
 	return 0;
 }
 
+#include "../gpu/drm/i915/i915_reg.h"
+#define MSG_CTL	0x45010
+#define IGD_OPERATION_TIMEOUT 10000     /* set timeout 10 seconds */
+
+static int reset_ivb_igd(struct pci_dev *dev, int probe)
+{
+	void __iomem *mmio_base;
+	unsigned long timeout;
+	u32 val;
+
+	if (probe)
+		return 0;
+
+	mmio_base = ioremap_nocache(pci_resource_start(dev, 0),
+				pci_resource_len(dev, 0));
+	if (!mmio_base)
+		return -ENOMEM;
+
+	/* Work Around */
+	writel(0x00000002, mmio_base + MSG_CTL);
+	/* Clobbering SOUTH_CHICKEN2 register is fine only if the next
+	 * driver loaded sets the right bits. However, this's a reset and
+	 * the bits have been set by i915 previously, so we clobber
+	 * SOUTH_CHICKEN2 register directly here.
+	 */
+	writel(0x00000005, mmio_base + SOUTH_CHICKEN2);
+	val = readl(mmio_base + PCH_PP_CONTROL) & 0xfffffffe;
+	writel(val, mmio_base + PCH_PP_CONTROL);
+	timeout = jiffies + msecs_to_jiffies(IGD_OPERATION_TIMEOUT);
+	while (time_before(jiffies, timeout)) {
+		val = readl(mmio_base + PCH_PP_STATUS);
+		if ((val & 0xB0000000) == 0)
+			break;
+		cpu_relax();
+	}
+	writel(0x00000002, mmio_base + 0xd0100);
+
+	iounmap(pci_resource_start(dev, 0));
+	return 0;
+}
+
 #define PCI_DEVICE_ID_INTEL_82599_SFP_VF   0x10ed
+#define PCI_DEVICE_ID_INTEL_IVB_M_VGA      0x0156
+#define PCI_DEVICE_ID_INTEL_IVB_M2_VGA     0x0166
 
 static const struct pci_dev_reset_methods pci_dev_reset_methods[] = {
 	{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82599_SFP_VF,
 		 reset_intel_82599_sfp_virtfn },
+	{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IVB_M_VGA,
+		reset_ivb_igd },
+	{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IVB_M2_VGA,
+		reset_ivb_igd },
 	{ PCI_VENDOR_ID_INTEL, PCI_ANY_ID,
 		reset_intel_generic_dev },
 	{ 0 }
-- 
1.6.0.rc1


> If we're doing FLR in a pass-through situation, where the host does
> the FLR but has no driver for the device, doing this in a quirk makes
> sense to me.
> 
> I tried to apply this patch, but it's whitespace-damaged.  Can you repost it?
> 


Thanks Bjorn, I repost it and can you try again?

> Bjorn
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