* [PATCH] PCI: Support hibmc VGA cards behind a misbehaving HiSilicon bridge
@ 2017-06-19 2:35 Daniel Axtens
2017-06-19 23:55 ` Bjorn Helgaas
0 siblings, 1 reply; 3+ messages in thread
From: Daniel Axtens @ 2017-06-19 2:35 UTC (permalink / raw)
To: linux-pci; +Cc: Daniel Axtens, Xinliang Liu, Rongrong Zou
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(+)
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
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] PCI: Support hibmc VGA cards behind a misbehaving HiSilicon bridge
2017-06-19 2:35 [PATCH] PCI: Support hibmc VGA cards behind a misbehaving HiSilicon bridge Daniel Axtens
@ 2017-06-19 23:55 ` Bjorn Helgaas
2017-06-20 0:28 ` Daniel Axtens
0 siblings, 1 reply; 3+ messages in thread
From: Bjorn Helgaas @ 2017-06-19 23:55 UTC (permalink / raw)
To: Daniel Axtens; +Cc: linux-pci, Xinliang Liu, Rongrong Zou
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
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] PCI: Support hibmc VGA cards behind a misbehaving HiSilicon bridge
2017-06-19 23:55 ` Bjorn Helgaas
@ 2017-06-20 0:28 ` Daniel Axtens
0 siblings, 0 replies; 3+ messages in thread
From: Daniel Axtens @ 2017-06-20 0:28 UTC (permalink / raw)
To: Bjorn Helgaas; +Cc: linux-pci, Xinliang Liu, Rongrong Zou
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
>>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2017-06-20 0:28 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-06-19 2:35 [PATCH] PCI: Support hibmc VGA cards behind a misbehaving HiSilicon bridge Daniel Axtens
2017-06-19 23:55 ` Bjorn Helgaas
2017-06-20 0:28 ` Daniel Axtens
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).