[PATCH v2 2/4] gpu/radeon: Move 64-bit MSI quirk from arch to driver

Benjamin Herrenschmidt benh at kernel.crashing.org
Thu Oct 2 10:33:39 EST 2014

A number of radeon cards have a HW limitation causing them to be
unable to generate the full 64-bit of address bits for MSIs. This
breaks MSIs on some platforms such as POWER machines.

We used to have a powerpc specific quirk to address that on a
single card, but this doesn't scale very well, this is better
put under control of the drivers who know precisely what a given
HW revision can do.

This moves the setting of the quirk flag to the radeon driver

Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
CC: <stable at vger.kernel.org>

v2: This is just adjusted to the new flag name

 arch/powerpc/kernel/pci_64.c            |  1 -
 drivers/gpu/drm/radeon/radeon_irq_kms.c | 10 ++++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c
index d41a831..5330f6d 100644
--- a/arch/powerpc/kernel/pci_64.c
+++ b/arch/powerpc/kernel/pci_64.c
@@ -271,5 +271,4 @@ static void quirk_radeon_32bit_msi(struct pci_dev *dev)
 	dev->no_64bit_msi = true;
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x68f2, quirk_radeon_32bit_msi);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0xaa68, quirk_radeon_32bit_msi);
diff --git a/drivers/gpu/drm/radeon/radeon_irq_kms.c b/drivers/gpu/drm/radeon/radeon_irq_kms.c
index 16807af..e760671 100644
--- a/drivers/gpu/drm/radeon/radeon_irq_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_irq_kms.c
@@ -202,6 +202,16 @@ static bool radeon_msi_ok(struct radeon_device *rdev)
 	if (rdev->flags & RADEON_IS_AGP)
 		return false;
+	/*
+	 * Older chips have a HW limitation, they can only generate 40 bits
+	 * of address for "64-bit" MSIs which breaks on some platforms, notably
+	 * IBM POWER servers, so we limit them
+	 */
+	if (rdev->family < CHIP_BONAIRE) {
+		dev_info(rdev->dev, "radeon: MSI limited to 32-bit\n");
+		rdev->pdev->no_64bit_msi = true;
+	}
 	/* force MSI on */
 	if (radeon_msi == 1)
 		return true;

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