From: Rob Clark <robdclark at chromium.org>
Add a build option to disable modesetting support. This is useful in
cases where the guest only needs to use the GPU in a headless mode, or
(such as in the CrOS usage) window surfaces are proxied to a host
compositor.
v2: Use more if (IS_ENABLED(...))
v3: Also permit the host to advertise no scanouts
Signed-off-by: Rob Clark <robdclark at chromium.org>
---
drivers/gpu/drm/virtio/Kconfig | 11 +++++++
drivers/gpu/drm/virtio/Makefile | 5 +++-
drivers/gpu/drm/virtio/virtgpu_drv.c | 6 +++-
drivers/gpu/drm/virtio/virtgpu_drv.h | 10 +++++++
drivers/gpu/drm/virtio/virtgpu_kms.c | 44 ++++++++++++++++++----------
5 files changed, 59 insertions(+), 17 deletions(-)
diff --git a/drivers/gpu/drm/virtio/Kconfig b/drivers/gpu/drm/virtio/Kconfig
index 51ec7c3240c9..ea06ff2aa4b4 100644
--- a/drivers/gpu/drm/virtio/Kconfig
+++ b/drivers/gpu/drm/virtio/Kconfig
@@ -11,3 +11,14 @@ config DRM_VIRTIO_GPU
QEMU based VMMs (like KVM or Xen).
If unsure say M.
+
+config DRM_VIRTIO_GPU_KMS
+ bool "Virtio GPU driver modesetting support"
+ depends on DRM_VIRTIO_GPU
+ default y
+ help
+ Enable modesetting support for virtio GPU driver. This can be
+ disabled in cases where only "headless" usage of the GPU is
+ required.
+
+ If unsure, say Y.
diff --git a/drivers/gpu/drm/virtio/Makefile b/drivers/gpu/drm/virtio/Makefile
index b99fa4a73b68..24c7ebe87032 100644
--- a/drivers/gpu/drm/virtio/Makefile
+++ b/drivers/gpu/drm/virtio/Makefile
@@ -4,8 +4,11 @@
# Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
virtio-gpu-y := virtgpu_drv.o virtgpu_kms.o virtgpu_gem.o virtgpu_vram.o \
- virtgpu_display.o virtgpu_vq.o \
+ virtgpu_vq.o \
virtgpu_fence.o virtgpu_object.o virtgpu_debugfs.o virtgpu_plane.o \
virtgpu_ioctl.o virtgpu_prime.o virtgpu_trace_points.o
+virtio-gpu-$(CONFIG_DRM_VIRTIO_GPU_KMS) += \
+ virtgpu_display.o
+
obj-$(CONFIG_DRM_VIRTIO_GPU) += virtio-gpu.o
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c
b/drivers/gpu/drm/virtio/virtgpu_drv.c
index ae97b98750b6..9cb7d6dd3da6 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.c
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
@@ -172,7 +172,11 @@ MODULE_AUTHOR("Alon Levy");
DEFINE_DRM_GEM_FOPS(virtio_gpu_driver_fops);
static const struct drm_driver driver = {
- .driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_RENDER |
DRIVER_ATOMIC,
+ .driver_features +#if defined(CONFIG_DRM_VIRTIO_GPU_KMS)
+ DRIVER_MODESET | DRIVER_ATOMIC |
+#endif
+ DRIVER_GEM | DRIVER_RENDER,
.open = virtio_gpu_driver_open,
.postclose = virtio_gpu_driver_postclose,
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h
b/drivers/gpu/drm/virtio/virtgpu_drv.h
index af6ffb696086..ffe8faf67247 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -426,8 +426,18 @@ virtio_gpu_cmd_set_scanout_blob(struct virtio_gpu_device
*vgdev,
uint32_t x, uint32_t y);
/* virtgpu_display.c */
+#if defined(CONFIG_DRM_VIRTIO_GPU_KMS)
int virtio_gpu_modeset_init(struct virtio_gpu_device *vgdev);
void virtio_gpu_modeset_fini(struct virtio_gpu_device *vgdev);
+#else
+static inline int virtio_gpu_modeset_init(struct virtio_gpu_device *vgdev)
+{
+ return 0;
+}
+static inline void virtio_gpu_modeset_fini(struct virtio_gpu_device *vgdev)
+{
+}
+#endif
/* virtgpu_plane.c */
uint32_t virtio_gpu_translate_format(uint32_t drm_fourcc);
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c
b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 27b7f14dae89..1d888e309d6b 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -161,7 +161,8 @@ int virtio_gpu_init(struct virtio_device *vdev, struct
drm_device *dev)
if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_VIRGL))
vgdev->has_virgl_3d = true;
#endif
- if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_EDID)) {
+ if (IS_ENABLED(CONFIG_DRM_VIRTIO_GPU_KMS) &&
+ virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_EDID)) {
vgdev->has_edid = true;
}
if (virtio_has_feature(vgdev->vdev, VIRTIO_RING_F_INDIRECT_DESC)) {
@@ -218,17 +219,28 @@ int virtio_gpu_init(struct virtio_device *vdev, struct
drm_device *dev)
goto err_vbufs;
}
- /* get display info */
- virtio_cread_le(vgdev->vdev, struct virtio_gpu_config,
- num_scanouts, &num_scanouts);
- vgdev->num_scanouts = min_t(uint32_t, num_scanouts,
- VIRTIO_GPU_MAX_SCANOUTS);
- if (!vgdev->num_scanouts) {
- DRM_ERROR("num_scanouts is zero\n");
- ret = -EINVAL;
- goto err_scanouts;
+ if (IS_ENABLED(CONFIG_DRM_VIRTIO_GPU_KMS)) {
+ /* get display info */
+ virtio_cread_le(vgdev->vdev, struct virtio_gpu_config,
+ num_scanouts, &num_scanouts);
+ vgdev->num_scanouts = min_t(uint32_t, num_scanouts,
+ VIRTIO_GPU_MAX_SCANOUTS);
+ if (!vgdev->num_scanouts) {
+ /*
+ * Having an EDID but no scanouts is non-sensical,
+ * but it is permitted to have no scanouts and no
+ * EDID (in which case DRIVER_MODESET and
+ * DRIVER_ATOMIC are not advertised)
+ */
+ if (vgdev->has_edid) {
+ DRM_ERROR("num_scanouts is zero\n");
+ ret = -EINVAL;
+ goto err_scanouts;
+ }
+ dev->driver_features &= ~(DRIVER_MODESET | DRIVER_ATOMIC);
+ }
+ DRM_INFO("number of scanouts: %d\n", num_scanouts);
}
- DRM_INFO("number of scanouts: %d\n", num_scanouts);
virtio_cread_le(vgdev->vdev, struct virtio_gpu_config,
num_capsets, &num_capsets);
@@ -246,10 +258,12 @@ int virtio_gpu_init(struct virtio_device *vdev, struct
drm_device *dev)
virtio_gpu_get_capsets(vgdev, num_capsets);
if (vgdev->has_edid)
virtio_gpu_cmd_get_edids(vgdev);
- virtio_gpu_cmd_get_display_info(vgdev);
- virtio_gpu_notify(vgdev);
- wait_event_timeout(vgdev->resp_wq, !vgdev->display_info_pending,
- 5 * HZ);
+ if (IS_ENABLED(CONFIG_DRM_VIRTIO_GPU_KMS) && vgdev->num_scanouts) {
+ virtio_gpu_cmd_get_display_info(vgdev);
+ virtio_gpu_notify(vgdev);
+ wait_event_timeout(vgdev->resp_wq, !vgdev->display_info_pending,
+ 5 * HZ);
+ }
return 0;
err_scanouts:
--
2.39.1
Gerd Hoffmann
2023-Feb-28 12:46 UTC
[PATCH v3] drm/virtio: Add option to disable KMS support
Hi,> + if (!vgdev->num_scanouts) { > + /* > + * Having an EDID but no scanouts is non-sensical, > + * but it is permitted to have no scanouts and no > + * EDID (in which case DRIVER_MODESET and > + * DRIVER_ATOMIC are not advertised) > + */ > + if (vgdev->has_edid) { > + DRM_ERROR("num_scanouts is zero\n");That error message isn't very clear. Also I'd suggest to just drop the edid check. It's about commands being supported by the device, not about the actual presence of an EDID blob, so the check doesn't look very useful to me. take care, Gerd