Messages in this thread | | | Date | Tue, 27 Jun 2023 22:35:34 +0800 | Subject | Re: [PATCH v7 6/8] PCI/VGA: Introduce is_boot_device function callback to vga_client_register | From | Sui Jingfeng <> |
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PING ?
On 2023/6/13 11:01, Sui Jingfeng wrote: > From: Sui Jingfeng <suijingfeng@loongson.cn> > > The vga_is_firmware_default() function is arch-dependent, it's probably > wrong if we simply remove the arch guard. As the VRAM BAR which contains > firmware framebuffer may move, while the lfb_base and lfb_size members of > the screen_info does not change accordingly. In short, it should take the > re-allocation of the PCI BAR into consideration. > > With the observation that device drivers or video aperture helpers may > have better knowledge about which PCI bar contains the firmware fb, > which could avoid the need to iterate all of the PCI BARs. But as a PCI > function at pci/vgaarb.c, vga_is_firmware_default() is not suitable to > make such an optimization since it is loaded too early. > > There are PCI display controllers that don't have a dedicated VRAM bar, > this function will lose its effectiveness in such a case. Luckily, the > device driver can provide an accurate workaround. > > Therefore, this patch introduces a callback that allows the device driver > to tell the VGAARB if the device is the default boot device. This patch > only intends to introduce the mechanism, while the implementation is left > to the device driver authors. Also honor the comment: "Clients have two > callback mechanisms they can use" > > Cc: Alex Deucher <alexander.deucher@amd.com> > Cc: Christian Konig <christian.koenig@amd.com> > Cc: Pan Xinhui <Xinhui.Pan@amd.com> > Cc: David Airlie <airlied@gmail.com> > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: Jani Nikula <jani.nikula@linux.intel.com> > Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> > Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> > Cc: Ben Skeggs <bskeggs@redhat.com> > Cc: Karol Herbst <kherbst@redhat.com> > Cc: Lyude Paul <lyude@redhat.com> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Cc: Alex Williamson <alex.williamson@redhat.com> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> > Cc: Maxime Ripard <mripard@kernel.org> > Cc: Thomas Zimmermann <tzimmermann@suse.de> > Cc: Hawking Zhang <Hawking.Zhang@amd.com> > Cc: Mario Limonciello <mario.limonciello@amd.com> > Cc: Lijo Lazar <lijo.lazar@amd.com> > Cc: YiPeng Chai <YiPeng.Chai@amd.com> > Cc: Bokun Zhang <Bokun.Zhang@amd.com> > Cc: Likun Gao <Likun.Gao@amd.com> > Cc: Ville Syrjala <ville.syrjala@linux.intel.com> > Cc: Jason Gunthorpe <jgg@ziepe.ca> > CC: Kevin Tian <kevin.tian@intel.com> > Cc: Cornelia Huck <cohuck@redhat.com> > Cc: Yishai Hadas <yishaih@nvidia.com> > Cc: Abhishek Sahu <abhsahu@nvidia.com> > Cc: Yi Liu <yi.l.liu@intel.com> > Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn> > --- > drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +- > drivers/gpu/drm/i915/display/intel_vga.c | 3 +-- > drivers/gpu/drm/nouveau/nouveau_vga.c | 2 +- > drivers/gpu/drm/radeon/radeon_device.c | 2 +- > drivers/pci/vgaarb.c | 21 ++++++++++++++++++++- > drivers/vfio/pci/vfio_pci_core.c | 2 +- > include/linux/vgaarb.h | 8 +++++--- > 7 files changed, 30 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c > index 5c7d40873ee2..7a096f2d5c16 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c > @@ -3960,7 +3960,7 @@ int amdgpu_device_init(struct amdgpu_device *adev, > /* this will fail for cards that aren't VGA class devices, just > * ignore it */ > if ((adev->pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA) > - vga_client_register(adev->pdev, amdgpu_device_vga_set_decode); > + vga_client_register(adev->pdev, amdgpu_device_vga_set_decode, NULL); > > px = amdgpu_device_supports_px(ddev); > > diff --git a/drivers/gpu/drm/i915/display/intel_vga.c b/drivers/gpu/drm/i915/display/intel_vga.c > index 286a0bdd28c6..98d7d4dffe9f 100644 > --- a/drivers/gpu/drm/i915/display/intel_vga.c > +++ b/drivers/gpu/drm/i915/display/intel_vga.c > @@ -115,7 +115,6 @@ intel_vga_set_decode(struct pci_dev *pdev, bool enable_decode) > > int intel_vga_register(struct drm_i915_private *i915) > { > - > struct pci_dev *pdev = to_pci_dev(i915->drm.dev); > int ret; > > @@ -127,7 +126,7 @@ int intel_vga_register(struct drm_i915_private *i915) > * then we do not take part in VGA arbitration and the > * vga_client_register() fails with -ENODEV. > */ > - ret = vga_client_register(pdev, intel_vga_set_decode); > + ret = vga_client_register(pdev, intel_vga_set_decode, NULL); > if (ret && ret != -ENODEV) > return ret; > > diff --git a/drivers/gpu/drm/nouveau/nouveau_vga.c b/drivers/gpu/drm/nouveau/nouveau_vga.c > index f8bf0ec26844..162b4f4676c7 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_vga.c > +++ b/drivers/gpu/drm/nouveau/nouveau_vga.c > @@ -92,7 +92,7 @@ nouveau_vga_init(struct nouveau_drm *drm) > return; > pdev = to_pci_dev(dev->dev); > > - vga_client_register(pdev, nouveau_vga_set_decode); > + vga_client_register(pdev, nouveau_vga_set_decode, NULL); > > /* don't register Thunderbolt eGPU with vga_switcheroo */ > if (pci_is_thunderbolt_attached(pdev)) > diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c > index afbb3a80c0c6..71f2ff39d6a1 100644 > --- a/drivers/gpu/drm/radeon/radeon_device.c > +++ b/drivers/gpu/drm/radeon/radeon_device.c > @@ -1425,7 +1425,7 @@ int radeon_device_init(struct radeon_device *rdev, > /* if we have > 1 VGA cards, then disable the radeon VGA resources */ > /* this will fail for cards that aren't VGA class devices, just > * ignore it */ > - vga_client_register(rdev->pdev, radeon_vga_set_decode); > + vga_client_register(rdev->pdev, radeon_vga_set_decode, NULL); > > if (rdev->flags & RADEON_IS_PX) > runtime = true; > diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c > index ceb914245383..c574898380f0 100644 > --- a/drivers/pci/vgaarb.c > +++ b/drivers/pci/vgaarb.c > @@ -53,6 +53,7 @@ struct vga_device { > bool bridge_has_one_vga; > bool is_firmware_default; /* device selected by firmware */ > unsigned int (*set_decode)(struct pci_dev *pdev, bool decode); > + bool (*is_boot_device)(struct pci_dev *pdev); > }; > > static LIST_HEAD(vga_list); > @@ -969,6 +970,10 @@ EXPORT_SYMBOL(vga_set_legacy_decoding); > * @set_decode callback: If a client can disable its GPU VGA resource, it > * will get a callback from this to set the encode/decode state. > * > + * @is_boot_device: callback to the device driver, query if a client is the > + * default boot device, as the device driver typically has better knowledge > + * if specific device is the boot device. But this callback is optional. > + * > * Rationale: we cannot disable VGA decode resources unconditionally, some > * single GPU laptops seem to require ACPI or BIOS access to the VGA registers > * to control things like backlights etc. Hopefully newer multi-GPU laptops do > @@ -984,7 +989,8 @@ EXPORT_SYMBOL(vga_set_legacy_decoding); > * Returns: 0 on success, -1 on failure > */ > int vga_client_register(struct pci_dev *pdev, > - unsigned int (*set_decode)(struct pci_dev *pdev, bool decode)) > + unsigned int (*set_decode)(struct pci_dev *pdev, bool decode), > + bool (*is_boot_device)(struct pci_dev *pdev)) > { > int ret = -ENODEV; > struct vga_device *vgadev; > @@ -996,6 +1002,7 @@ int vga_client_register(struct pci_dev *pdev, > goto bail; > > vgadev->set_decode = set_decode; > + vgadev->is_boot_device = is_boot_device; > ret = 0; > > bail: > @@ -1523,6 +1530,18 @@ static int pci_notify(struct notifier_block *nb, unsigned long action, > notify = vga_arbiter_add_pci_device(pdev); > else if (action == BUS_NOTIFY_DEL_DEVICE) > notify = vga_arbiter_del_pci_device(pdev); > + else if (action == BUS_NOTIFY_BOUND_DRIVER) { > + struct vga_device *vgadev = vgadev_find(pdev); > + bool boot_dev = false; > + > + if (vgadev && vgadev->is_boot_device) > + boot_dev = vgadev->is_boot_device(pdev); > + > + if (boot_dev) { > + vgaarb_info(&pdev->dev, "Set as boot device (dictated by driver)\n"); > + vga_set_default_device(pdev); > + } > + } > > vgaarb_dbg(dev, "%s: action = %lu\n", __func__, action); > > diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c > index a5ab416cf476..2a8873a330ba 100644 > --- a/drivers/vfio/pci/vfio_pci_core.c > +++ b/drivers/vfio/pci/vfio_pci_core.c > @@ -2067,7 +2067,7 @@ static int vfio_pci_vga_init(struct vfio_pci_core_device *vdev) > if (ret) > return ret; > > - ret = vga_client_register(pdev, vfio_pci_set_decode); > + ret = vga_client_register(pdev, vfio_pci_set_decode, NULL); > if (ret) > return ret; > vga_set_legacy_decoding(pdev, vfio_pci_set_decode(pdev, false)); > diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h > index 97129a1bbb7d..dfde5a6ba55a 100644 > --- a/include/linux/vgaarb.h > +++ b/include/linux/vgaarb.h > @@ -33,7 +33,8 @@ struct pci_dev *vga_default_device(void); > void vga_set_default_device(struct pci_dev *pdev); > int vga_remove_vgacon(struct pci_dev *pdev); > int vga_client_register(struct pci_dev *pdev, > - unsigned int (*set_decode)(struct pci_dev *pdev, bool state)); > + unsigned int (*set_decode)(struct pci_dev *pdev, bool state), > + bool (*is_boot_device)(struct pci_dev *pdev)); > #else /* CONFIG_VGA_ARB */ > static inline void vga_set_legacy_decoding(struct pci_dev *pdev, > unsigned int decodes) > @@ -59,7 +60,8 @@ static inline int vga_remove_vgacon(struct pci_dev *pdev) > return 0; > } > static inline int vga_client_register(struct pci_dev *pdev, > - unsigned int (*set_decode)(struct pci_dev *pdev, bool state)) > + unsigned int (*set_decode)(struct pci_dev *pdev, bool state), > + bool (*is_boot_device)(struct pci_dev *pdev)) > { > return 0; > } > @@ -97,7 +99,7 @@ static inline int vga_get_uninterruptible(struct pci_dev *pdev, > > static inline void vga_client_unregister(struct pci_dev *pdev) > { > - vga_client_register(pdev, NULL); > + vga_client_register(pdev, NULL, NULL); > } > > #endif /* LINUX_VGA_H */
-- Jingfeng
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