From 91ed6fd2c383bb8f02d66e98b4a4d2f7207249dc Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Fri, 3 Oct 2014 15:18:59 +1000 Subject: [PATCH] gpu/radeon: Set flag to indicate broken 64-bit MSI Some radeon ASICs don't support all 64 address bits of MSIs despite advertising support for 64-bit MSIs in their configuration space. This breaks on systems such as IBM POWER7/8, where 64-bit MSIs can be assigned with some of the high address bits set. This makes use of the newly introduced "no_64bit_msi" flag in structure pci_dev to allow the MSI allocation code to fallback to 32-bit MSIs on those adapters. Signed-off-by: Benjamin Herrenschmidt Reviewed-by: Alex Deucher CC: --- Adding Alex's review tag. Patch to the driver is identical to the reviewed one, I dropped the arch/powerpc hunk rewrote the subject and cset comment. --- drivers/gpu/drm/radeon/radeon_irq_kms.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/gpu/drm/radeon/radeon_irq_kms.c b/drivers/gpu/drm/radeon/radeon_irq_kms.c index 7784911d78ef..00fc59762e0d 100644 --- a/drivers/gpu/drm/radeon/radeon_irq_kms.c +++ b/drivers/gpu/drm/radeon/radeon_irq_kms.c @@ -185,6 +185,16 @@ 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 = 1; + } + /* force MSI on */ if (radeon_msi == 1) return true;