From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f196.google.com ([209.85.220.196]:33276 "EHLO mail-qk0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750722AbdGLFLY (ORCPT ); Wed, 12 Jul 2017 01:11:24 -0400 Received: by mail-qk0-f196.google.com with SMTP id a66so802937qkb.0 for ; Tue, 11 Jul 2017 22:11:23 -0700 (PDT) From: Daniel Axtens To: linux-pci@vger.kernel.org Cc: Daniel Axtens , Xinliang Liu , Rongrong Zou Subject: [PATCH v4] PCI: Support hibmc VGA cards behind a misbehaving HiSilicon bridge Date: Wed, 12 Jul 2017 15:08:11 +1000 Message-Id: <20170712050811.3620-1-dja@axtens.net> Sender: linux-pci-owner@vger.kernel.org List-ID: The HiSilicon D05 board has some PCI bridges (PCI ID 19e5:1610) that are not spec-compliant: the VGA Enable bit is hardwired to 0 and writes do not change it. The HiSilicon engineers report that the bridge does not forward the 0xa0000-0xbffff mem range and the 0x3b0-0x3bb and 0x3c0-0x3df I/O ranges. Because the VGA Enable bit is hardwired to 0, the VGA arbiter refuses to mark any card behind it as the boot device. This breaks Xorg auto-detection. However, the hibmc VGA card (PCI ID 19e5:1711) has been tested and is known to work when behind these bridges. (It does not require the legacy resources to operate.) Provide a quirk so that this combination of bridge and card is eligible to be the default VGA card. This fixes Xorg auto-detection on the D05. Cc: Xinliang Liu Cc: Rongrong Zou Signed-off-by: Daniel Axtens --- v3: fix commit message v4: fix comment (forgot to git add/git commit, sorry for the noise) --- drivers/pci/quirks.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 16e6cd86ad71..b42324cba29e 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -25,6 +25,7 @@ #include #include #include +#include #include /* isa_dma_bridge_buggy */ #include "pci.h" @@ -4664,3 +4665,52 @@ static void quirk_intel_no_flr(struct pci_dev *dev) } DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1502, quirk_intel_no_flr); DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1503, quirk_intel_no_flr); + +/* + * The HiSilicon D05 board has some PCI bridges (PCI ID 19e5:1610) + * that are not spec-compliant: the VGA Enable bit is hardwired to 0 + * and writes do not change it. The bridge does not forward legacy + * memory or I/O resources. + * + * Because the VGA Enable bit is hardwired to 0, the VGA arbiter + * refuses to mark any card behind it as the boot device. However, the + * hibmc VGA card (PCI ID 19e5:1711) has been tested and is known to + * work when behind these bridges. + * + * If we have this bridge, this card, and no default card already, + * mark the card as default. + */ +static void hibmc_fixup_vgaarb(struct pci_dev *pdev) +{ + struct pci_dev *bridge; + struct pci_bus *bus; + u16 config; + + bus = pdev->bus; + bridge = bus->self; + if (!bridge) + return; + + if (!pci_is_bridge(bridge)) + return; + + if (bridge->vendor != PCI_VENDOR_ID_HUAWEI || + bridge->device != 0x1610) + return; + + pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, + &config); + if (config & PCI_BRIDGE_CTL_VGA) { + /* + * Weirdly, this bridge *is* spec compliant, so bail + * and let vgaarb do its job + */ + return; + } + + if (vga_default_device()) + return; + + vga_set_default_device(pdev); +} +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_HUAWEI, 0x1711, hibmc_fixup_vgaarb); -- 2.11.0