| Message ID | 20170619023528.11532-1-dja@axtens.net (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
Hi Daniel, On Mon, Jun 19, 2017 at 12:35:28PM +1000, Daniel Axtens wrote: > The HiSilicon D05 board has some PCI bridges (PCI ID 19e5:1610) that > are not spec-compliant: they do not set the VGA Enable bit when a VGA > card is behind the bridge. This breaks Xorg auto-detection. I don't understand what is not spec-compliant about this. The VGA Enable bit (PCI_BRIDGE_CTL_VGA) is a read/write bit, and the bridge itself is not responsible for figuring out whether it has a VGA card below it. Some software (firmware/OS/etc) that enumerates the hierarchy is responsible for setting PCI_BRIDGE_CTL_VGA if desired. > Despite this, the hibmc VGA card (PCI ID 19e5:1711) is known to work > when behind these bridges. > > Provide a quirk so that this combination of bridge and card is eligible > to be the default VGA card. > > This fixes Xorg auto-detection. > > Cc: Xinliang Liu <z.liuxinliang@hisilicon.com> > Cc: Rongrong Zou <zourongrong@gmail.com> > Signed-off-by: Daniel Axtens <dja@axtens.net> > --- > drivers/pci/quirks.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 46 insertions(+) > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > index 16e6cd86ad71..9475d6056dd3 100644 > --- a/drivers/pci/quirks.c > +++ b/drivers/pci/quirks.c > @@ -25,6 +25,7 @@ > #include <linux/sched.h> > #include <linux/ktime.h> > #include <linux/mm.h> > +#include <linux/vgaarb.h> > #include <asm/dma.h> /* isa_dma_bridge_buggy */ > #include "pci.h" > > @@ -4664,3 +4665,48 @@ 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 hibmc card on a HiSilicon D05 board sits behind a non-compliant > + * bridge. The bridge doesn't advertise the PCI_BRIDGE_CTL_VGA bit in > + * its config space. This prevents the vgaarb from marking a card > + * behind it as boot VGA device. > + * > + * However, the hibmc card is known to still work, so if we have that > + * card behind that particular bridge (19e5:1610), mark it as the > + * default device if none has been detected. > + */ > +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 >
Hi Bjorn, > On Mon, Jun 19, 2017 at 12:35:28PM +1000, Daniel Axtens wrote: >> The HiSilicon D05 board has some PCI bridges (PCI ID 19e5:1610) that >> are not spec-compliant: they do not set the VGA Enable bit when a VGA >> card is behind the bridge. This breaks Xorg auto-detection. > > I don't understand what is not spec-compliant about this. The VGA > Enable bit (PCI_BRIDGE_CTL_VGA) is a read/write bit, and the bridge > itself is not responsible for figuring out whether it has a VGA card > below it. > > Some software (firmware/OS/etc) that enumerates the hierarchy is > responsible for setting PCI_BRIDGE_CTL_VGA if desired. Ah sorry, this was poorly understood/expressed on my part. The bit is fixed in hardware: I wrote a 1 to it, read it back immediately, and got a 0. I'll respin with a corrected comment and commit message. Regards, Daniel > >> Despite this, the hibmc VGA card (PCI ID 19e5:1711) is known to work >> when behind these bridges. >> >> Provide a quirk so that this combination of bridge and card is eligible >> to be the default VGA card. >> >> This fixes Xorg auto-detection. >> >> Cc: Xinliang Liu <z.liuxinliang@hisilicon.com> >> Cc: Rongrong Zou <zourongrong@gmail.com> >> Signed-off-by: Daniel Axtens <dja@axtens.net> >> --- >> drivers/pci/quirks.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 46 insertions(+) >> >> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c >> index 16e6cd86ad71..9475d6056dd3 100644 >> --- a/drivers/pci/quirks.c >> +++ b/drivers/pci/quirks.c >> @@ -25,6 +25,7 @@ >> #include <linux/sched.h> >> #include <linux/ktime.h> >> #include <linux/mm.h> >> +#include <linux/vgaarb.h> >> #include <asm/dma.h> /* isa_dma_bridge_buggy */ >> #include "pci.h" >> >> @@ -4664,3 +4665,48 @@ 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 hibmc card on a HiSilicon D05 board sits behind a non-compliant >> + * bridge. The bridge doesn't advertise the PCI_BRIDGE_CTL_VGA bit in >> + * its config space. This prevents the vgaarb from marking a card >> + * behind it as boot VGA device. >> + * >> + * However, the hibmc card is known to still work, so if we have that >> + * card behind that particular bridge (19e5:1610), mark it as the >> + * default device if none has been detected. >> + */ >> +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 >>
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 16e6cd86ad71..9475d6056dd3 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -25,6 +25,7 @@ #include <linux/sched.h> #include <linux/ktime.h> #include <linux/mm.h> +#include <linux/vgaarb.h> #include <asm/dma.h> /* isa_dma_bridge_buggy */ #include "pci.h" @@ -4664,3 +4665,48 @@ 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 hibmc card on a HiSilicon D05 board sits behind a non-compliant + * bridge. The bridge doesn't advertise the PCI_BRIDGE_CTL_VGA bit in + * its config space. This prevents the vgaarb from marking a card + * behind it as boot VGA device. + * + * However, the hibmc card is known to still work, so if we have that + * card behind that particular bridge (19e5:1610), mark it as the + * default device if none has been detected. + */ +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);
The HiSilicon D05 board has some PCI bridges (PCI ID 19e5:1610) that are not spec-compliant: they do not set the VGA Enable bit when a VGA card is behind the bridge. This breaks Xorg auto-detection. Despite this, the hibmc VGA card (PCI ID 19e5:1711) is known to work when behind these bridges. Provide a quirk so that this combination of bridge and card is eligible to be the default VGA card. This fixes Xorg auto-detection. Cc: Xinliang Liu <z.liuxinliang@hisilicon.com> Cc: Rongrong Zou <zourongrong@gmail.com> Signed-off-by: Daniel Axtens <dja@axtens.net> --- drivers/pci/quirks.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+)