On 12/30/25 00:58, Zack Rusin wrote:
> Register a devm action on the virtio device to restore the system
> framebuffer (efifb/simpledrm) if the driver's probe fails after
> removing the firmware framebuffer.
>
> Unlike PCI drivers, virtio-gpu cannot use the
> devm_aperture_remove_conflicting_pci_devices() helper because the
> PCI device is managed by the virtio-pci driver, not by virtio-gpu.
> When virtio-gpu probe fails, the PCI device remains bound to
> virtio-pci, so devm actions registered on the PCI device won't fire.
>
> Instead, register the sysfb restore action on the virtio device
> (&vdev->dev) which will be released if virtio-gpu probe fails.
> Cancel the action after successful probe since the driver is now
> responsible for display output.
>
> This only applies to VGA devices where aperture_remove_conflicting_pci_devices()
> is called to remove the firmware framebuffer.
>
> Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
> Cc: David Airlie <airlied@redhat.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: Dmitry Osipenko <dmitry.osipenko@collabora.com>
> Cc: Gurchetan Singh <gurchetansingh@chromium.org>
> Cc: Chia-I Wu <olvaffe@gmail.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Simona Vetter <simona@ffwll.ch>
> Cc: dri-devel@lists.freedesktop.org
> Cc: virtualization@lists.linux.dev
> Cc: linux-kernel@vger.kernel.org
> ---
> drivers/gpu/drm/virtio/virtgpu_drv.c | 29 ++++++++++++++++++++++++++++
> 1 file changed, 29 insertions(+)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
> index a5ce96fb8a1d..13cc8396fc78 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
> @@ -30,6 +30,7 @@
> #include <linux/module.h>
> #include <linux/pci.h>
> #include <linux/poll.h>
> +#include <linux/sysfb.h>
> #include <linux/vgaarb.h>
> #include <linux/wait.h>
>
> @@ -52,6 +53,11 @@ static int virtio_gpu_modeset = -1;
> MODULE_PARM_DESC(modeset, "Disable/Enable modesetting");
> module_param_named(modeset, virtio_gpu_modeset, int, 0400);
>
> +static void virtio_gpu_restore_sysfb(void *unused)
> +{
> + sysfb_restore();
> +}
> +
> static int virtio_gpu_pci_quirk(struct drm_device *dev)
> {
> struct pci_dev *pdev = to_pci_dev(dev->dev);
> @@ -75,6 +81,7 @@ static int virtio_gpu_probe(struct virtio_device *vdev)
> {
> struct drm_device *dev;
> int ret;
> + bool sysfb_restore_registered = false;
>
> if (drm_firmware_drivers_only() && virtio_gpu_modeset == -1)
> return -EINVAL;
> @@ -97,6 +104,21 @@ static int virtio_gpu_probe(struct virtio_device *vdev)
> ret = virtio_gpu_pci_quirk(dev);
> if (ret)
> goto err_free;
> +
> + /*
> + * For VGA devices, register sysfb restore on the virtio device.
> + * We can't use devm_aperture_remove_conflicting_pci_devices()
> + * because the PCI device is managed by virtio-pci, not us.
> + * Register on &vdev->dev so it fires if our probe fails.
> + */
> + if (pci_is_vga(to_pci_dev(vdev->dev.parent))) {
> + ret = devm_add_action_or_reset(&vdev->dev,
> + virtio_gpu_restore_sysfb,
> + NULL);
> + if (ret)
> + goto err_free;
> + sysfb_restore_registered = true;
> + }
> }
>
> dma_set_max_seg_size(dev->dev, dma_max_mapping_size(dev->dev) ?: UINT_MAX);
> @@ -110,6 +132,13 @@ static int virtio_gpu_probe(struct virtio_device *vdev)
>
> drm_client_setup(vdev->priv, NULL);
>
> + /*
> + * Probe succeeded - cancel sysfb restore. We're now responsible
> + * for display output.
> + */
> + if (sysfb_restore_registered)
> + devm_remove_action(&vdev->dev, virtio_gpu_restore_sysfb, NULL);
> +
> return 0;
>
> err_deinit:
Acked-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
--
Best regards,
Dmitry