From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Date: Wed, 12 Jul 2017 15:04:30 -0500 From: Bjorn Helgaas To: Daniel Axtens Subject: Re: [PATCH v4] PCI: Support hibmc VGA cards behind a misbehaving HiSilicon bridge Message-ID: <20170712200430.GI14614@bhelgaas-glaptop.roam.corp.google.com> References: <20170712050811.3620-1-dja@axtens.net> MIME-Version: 1.0 In-Reply-To: <20170712050811.3620-1-dja@axtens.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-pci@vger.kernel.org, Will Deacon , Xinliang Liu , Catalin Marinas , Rongrong Zou , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+bjorn=helgaas.com@lists.infradead.org List-ID: [+cc Catalin, Will, linux-arm-kernel] On Wed, Jul 12, 2017 at 03:08:11PM +1000, Daniel Axtens wrote: > 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); Is this quirk useful on any arch other than arm64? Per drivers/pci/dwc/Kconfig, CONFIG_PCI_HISI depends on CONFIG_ARM64. Would it make sense to put this quirk in arch/arm64/kernel/pci.c? _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel From mboxrd@z Thu Jan 1 00:00:00 1970 From: helgaas@kernel.org (Bjorn Helgaas) Date: Wed, 12 Jul 2017 15:04:30 -0500 Subject: [PATCH v4] PCI: Support hibmc VGA cards behind a misbehaving HiSilicon bridge In-Reply-To: <20170712050811.3620-1-dja@axtens.net> References: <20170712050811.3620-1-dja@axtens.net> Message-ID: <20170712200430.GI14614@bhelgaas-glaptop.roam.corp.google.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org [+cc Catalin, Will, linux-arm-kernel] On Wed, Jul 12, 2017 at 03:08:11PM +1000, Daniel Axtens wrote: > 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); Is this quirk useful on any arch other than arm64? Per drivers/pci/dwc/Kconfig, CONFIG_PCI_HISI depends on CONFIG_ARM64. Would it make sense to put this quirk in arch/arm64/kernel/pci.c?