From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org ([63.228.1.57]:40402 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753757AbaJGFix (ORCPT ); Tue, 7 Oct 2014 01:38:53 -0400 Message-ID: <1412656686.30859.121.camel@pasglop> Subject: [PATCH v3 3/7] gpu/radeon: Set flag to indicate broken 64-bit MSI From: Benjamin Herrenschmidt To: Alex Deucher , Bjorn Helgaas Cc: Dave Airlie , Brian King , Takashi Iwai , linux-pci@vger.kernel.org, Yijing Wang , Anton Blanchard , linuxppc-dev@ozlabs.org Date: Tue, 07 Oct 2014 15:38:06 +1100 Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org List-ID: 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 16807af..c74f12d 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 = 1; + } + /* force MSI on */ if (radeon_msi == 1) return true;