On Tue, Jul 06, 2021 at 05:21:42PM +0800, Huacai Chen wrote:
> Hi, Daniel,
>
> On Tue, Jul 6, 2021 at 4:21 PM Daniel Vetter <daniel@xxxxxxxx> wrote:
> >
> > On Mon, Jul 05, 2021 at 06:05:03PM +0800, Huacai Chen wrote:
> > > Currently, vga_arb_device_init() selects the first probed VGA device
> > > with VGA legacy resources enabled as the default device. However, some
> > > BMC-based VGA cards (e.g., AST2500 and HiSilicon D05) don't enable VGA
> > > legacy resources because their built-in upstream bridges don't support
> > > PCI_BRIDGE_CTL_VGA. This makes "no default VGA card" and breaks X.org
> > > auto-detection.
> > >
> > > Commit a37c0f48950b56f6ef2e ("vgaarb: Select a default VGA device even
> > > if there's no legacy VGA") try to solve this problem but fails on some
> > > platforms, because it relies on the initcall order:
> > >
> > > We should call vga_arb_device_init() after PCI enumeration, otherwise it
> > > may fail to select the default VGA device. Since vga_arb_device_init()
> > > and PCI enumeration function (i.e., pcibios_init() or acpi_init()) are
> > > both wrapped by subsys_initcall(), their sequence is not assured. So, it
> > > is possible to use subsys_initcall_sync() instead of subsys_initcall()
> > > to wrap vga_arb_device_init().
> > >
> > > However, the above approach still has drawbacks, it cannot handle the
> > > cases that a VGA card is hot-plugged, or the gpu driver is compiled as a
> > > module.
> > >
> > > So, as suggested by Bjorn Helgaas, this patch rework the selection:
> > > 1, Remove direct vga_arb_select_default_device() calls in vga_arb_
> > > device_init().
> > > 2, Rename vga_arb_select_default_device() to vga_arb_update_default_
> > > device(), which selects the first probed VGA device as the default
> > > (whether legacy resources enabled or not), and update the default
> > > device if a better one is found (device with legacy resources enabled
> > > is better, device owns the firmware framebuffer is even better).
> > > 3, Every time a new VGA device is probed, vga_arbiter_add_pci_device()
> > > is called, and vga_arb_update_default_device() is also called. So the
> > > hotplug case and the module case can also be handled.
> > >
> > > Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> >
> > Sounds reasonable, but because this is defacto pci stuff that just isn't
> > in drivers/pci (maybe we should move it) I'll defer to Bjorn's review
> > before I apply this patch.
> > -Daniel
> This (move to drivers/pci) has been disscussed before, I think that
> can be another patch.
Oh definitely, I just wanted to explain why I won't simply apply this
without Bjorn's review.
-Daniel
>
> Huacai
> >
> > > ---
> > > drivers/gpu/vga/vgaarb.c | 219 +++++++++++++++++----------------------
> > > 1 file changed, 97 insertions(+), 122 deletions(-)
> > >
> > > diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
> > > index 949fde433ea2..07770aae3aaf 100644
> > > --- a/drivers/gpu/vga/vgaarb.c
> > > +++ b/drivers/gpu/vga/vgaarb.c
> > > @@ -586,6 +586,97 @@ void vga_put(struct pci_dev *pdev, unsigned int rsrc)
> > > }
> > > EXPORT_SYMBOL(vga_put);
> > >
> > > +#if defined(CONFIG_ACPI)
> > > +static bool vga_arb_integrated_gpu(struct device *dev)
> > > +{
> > > + struct acpi_device *adev = ACPI_COMPANION(dev);
> > > +
> > > + return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID);
> > > +}
> > > +#else
> > > +static bool vga_arb_integrated_gpu(struct device *dev)
> > > +{
> > > + return false;
> > > +}
> > > +#endif
> > > +
> > > +static void vga_arb_update_default_device(struct vga_device *vgadev)
> > > +{
> > > + struct pci_dev *pdev = vgadev->pdev;
> > > + struct device *dev = &pdev->dev;
> > > + struct vga_device *vgadev_default;
> > > +#if defined(CONFIG_X86) || defined(CONFIG_IA64)
> > > + int i;
> > > + unsigned long flags;
> > > + u64 base = screen_info.lfb_base;
> > > + u64 size = screen_info.lfb_size;
> > > + u64 limit;
> > > + resource_size_t start, end;
> > > +#endif
> > > +
> > > + /* Deal with VGA default device. Use first enabled one
> > > + * by default if arch doesn't have it's own hook
> > > + */
> > > + if (!vga_default_device()) {
> > > + if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)
> > > + vgaarb_info(dev, "setting as boot VGA device\n");
> > > + else
> > > + vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n");
> > > + vga_set_default_device(pdev);
> > > + }
> > > +
> > > + vgadev_default = vgadev_find(vga_default);
> > > +
> > > + /* Overridden by a better device */
> > > + if (vgadev_default && ((vgadev_default->owns & VGA_RSRC_LEGACY_MASK) == 0)
> > > + && ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) {
> > > + vgaarb_info(dev, "overriding boot VGA device\n");
> > > + vga_set_default_device(pdev);
> > > + }
> > > +
> > > + if (vga_arb_integrated_gpu(dev)) {
> > > + vgaarb_info(dev, "overriding boot VGA device\n");
> > > + vga_set_default_device(pdev);
> > > + }
> > > +
> > > +#if defined(CONFIG_X86) || defined(CONFIG_IA64)
> > > + if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
> > > + base |= (u64)screen_info.ext_lfb_base << 32;
> > > +
> > > + limit = base + size;
> > > +
> > > + /*
> > > + * Override vga_arbiter_add_pci_device()'s I/O based detection
> > > + * as it may take the wrong device (e.g. on Apple system under
> > > + * EFI).
> > > + *
> > > + * Select the device owning the boot framebuffer if there is
> > > + * one.
> > > + */
> > > +
> > > + /* Does firmware framebuffer belong to us? */
> > > + for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
> > > + flags = pci_resource_flags(vgadev->pdev, i);
> > > +
> > > + if ((flags & IORESOURCE_MEM) == 0)
> > > + continue;
> > > +
> > > + start = pci_resource_start(vgadev->pdev, i);
> > > + end = pci_resource_end(vgadev->pdev, i);
> > > +
> > > + if (!start || !end)
> > > + continue;
> > > +
> > > + if (base < start || limit >= end)
> > > + continue;
> > > +
> > > + if (vgadev->pdev != vga_default_device())
> > > + vgaarb_info(dev, "overriding boot device\n");
> > > + vga_set_default_device(vgadev->pdev);
> > > + }
> > > +#endif
> > > +}
> > > +
> > > /*
> > > * Rules for using a bridge to control a VGA descendant decoding: if a bridge
> > > * has only one VGA descendant then it can be used to control the VGA routing
> > > @@ -643,6 +734,11 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
> > > }
> > > new_bus = new_bus->parent;
> > > }
> > > +
> > > + if (vgadev->bridge_has_one_vga == true)
> > > + vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n");
> > > + else
> > > + vgaarb_info(&vgadev->pdev->dev, "no bridge control possible\n");
> > > }
> > >
> > > /*
> > > @@ -713,15 +809,7 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
> > > bus = bus->parent;
> > > }
> > >
> > > - /* Deal with VGA default device. Use first enabled one
> > > - * by default if arch doesn't have it's own hook
> > > - */
> > > - if (vga_default == NULL &&
> > > - ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) {
> > > - vgaarb_info(&pdev->dev, "setting as boot VGA device\n");
> > > - vga_set_default_device(pdev);
> > > - }
> > > -
> > > + vga_arb_update_default_device(vgadev);
> > > vga_arbiter_check_bridge_sharing(vgadev);
> > >
> > > /* Add to the list */
> > > @@ -1451,111 +1539,10 @@ static struct miscdevice vga_arb_device = {
> > > MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops
> > > };
> > >
> > > -#if defined(CONFIG_ACPI)
> > > -static bool vga_arb_integrated_gpu(struct device *dev)
> > > -{
> > > - struct acpi_device *adev = ACPI_COMPANION(dev);
> > > -
> > > - return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID);
> > > -}
> > > -#else
> > > -static bool vga_arb_integrated_gpu(struct device *dev)
> > > -{
> > > - return false;
> > > -}
> > > -#endif
> > > -
> > > -static void __init vga_arb_select_default_device(void)
> > > -{
> > > - struct pci_dev *pdev, *found = NULL;
> > > - struct vga_device *vgadev;
> > > -
> > > -#if defined(CONFIG_X86) || defined(CONFIG_IA64)
> > > - u64 base = screen_info.lfb_base;
> > > - u64 size = screen_info.lfb_size;
> > > - u64 limit;
> > > - resource_size_t start, end;
> > > - unsigned long flags;
> > > - int i;
> > > -
> > > - if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
> > > - base |= (u64)screen_info.ext_lfb_base << 32;
> > > -
> > > - limit = base + size;
> > > -
> > > - list_for_each_entry(vgadev, &vga_list, list) {
> > > - struct device *dev = &vgadev->pdev->dev;
> > > - /*
> > > - * Override vga_arbiter_add_pci_device()'s I/O based detection
> > > - * as it may take the wrong device (e.g. on Apple system under
> > > - * EFI).
> > > - *
> > > - * Select the device owning the boot framebuffer if there is
> > > - * one.
> > > - */
> > > -
> > > - /* Does firmware framebuffer belong to us? */
> > > - for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
> > > - flags = pci_resource_flags(vgadev->pdev, i);
> > > -
> > > - if ((flags & IORESOURCE_MEM) == 0)
> > > - continue;
> > > -
> > > - start = pci_resource_start(vgadev->pdev, i);
> > > - end = pci_resource_end(vgadev->pdev, i);
> > > -
> > > - if (!start || !end)
> > > - continue;
> > > -
> > > - if (base < start || limit >= end)
> > > - continue;
> > > -
> > > - if (!vga_default_device())
> > > - vgaarb_info(dev, "setting as boot device\n");
> > > - else if (vgadev->pdev != vga_default_device())
> > > - vgaarb_info(dev, "overriding boot device\n");
> > > - vga_set_default_device(vgadev->pdev);
> > > - }
> > > - }
> > > -#endif
> > > -
> > > - if (!vga_default_device()) {
> > > - list_for_each_entry_reverse(vgadev, &vga_list, list) {
> > > - struct device *dev = &vgadev->pdev->dev;
> > > - u16 cmd;
> > > -
> > > - pdev = vgadev->pdev;
> > > - pci_read_config_word(pdev, PCI_COMMAND, &cmd);
> > > - if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {
> > > - found = pdev;
> > > - if (vga_arb_integrated_gpu(dev))
> > > - break;
> > > - }
> > > - }
> > > - }
> > > -
> > > - if (found) {
> > > - vgaarb_info(&found->dev, "setting as boot device (VGA legacy resources not available)\n");
> > > - vga_set_default_device(found);
> > > - return;
> > > - }
> > > -
> > > - if (!vga_default_device()) {
> > > - vgadev = list_first_entry_or_null(&vga_list,
> > > - struct vga_device, list);
> > > - if (vgadev) {
> > > - struct device *dev = &vgadev->pdev->dev;
> > > - vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n");
> > > - vga_set_default_device(vgadev->pdev);
> > > - }
> > > - }
> > > -}
> > > -
> > > static int __init vga_arb_device_init(void)
> > > {
> > > int rc;
> > > struct pci_dev *pdev;
> > > - struct vga_device *vgadev;
> > >
> > > rc = misc_register(&vga_arb_device);
> > > if (rc < 0)
> > > @@ -1571,18 +1558,6 @@ static int __init vga_arb_device_init(void)
> > > PCI_ANY_ID, pdev)) != NULL)
> > > vga_arbiter_add_pci_device(pdev);
> > >
> > > - list_for_each_entry(vgadev, &vga_list, list) {
> > > - struct device *dev = &vgadev->pdev->dev;
> > > -
> > > - if (vgadev->bridge_has_one_vga)
> > > - vgaarb_info(dev, "bridge control possible\n");
> > > - else
> > > - vgaarb_info(dev, "no bridge control possible\n");
> > > - }
> > > -
> > > - vga_arb_select_default_device();
> > > -
> > > - pr_info("loaded\n");
> > > return rc;
> > > }
> > > subsys_initcall(vga_arb_device_init);
> > > --
> > > 2.27.0
> > >
> >
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
