[RFCv1 11/12] drm: Atomic modeset ioctl

Rob Clark robdclark at gmail.com
Mon Oct 7 15:55:47 CEST 2013


On Mon, Oct 7, 2013 at 9:28 AM, Ville Syrjälä
<ville.syrjala at linux.intel.com> wrote:
> On Sat, Oct 05, 2013 at 08:45:49PM -0400, Rob Clark wrote:
>> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>
>> The atomic modeset ioctl cna be used to push any number of new values
>> for object properties. The driver can then check the full device
>> configuration as single unit, and try to apply the changes atomically.
>>
>> The ioctl simply takes a list of object IDs and property IDs and their
>> values. For setting values to blob properties, the property value
>> indicates the length of the data, and the actual data is passed via
>> another blob pointer.
>>
>> The caller can demand non-blocking operation from the ioctl, and if the
>> driver can't satisfy that requirement an error will be returned.
>>
>> The caller can also request to receive asynchronous completion events
>> after the operation has reached the hardware. An event is sent for each
>> object specified by the caller, whether or not the actual state of
>> that object changed. Each event also carries a framebuffer ID, which
>> indicates to user space that the specified object is no longer
>> accessing that framebuffer.
>>
>> TODO: detailed error reporting?
>>
>> v1: original
>> v2: rebase on uapi changes, and drm state structs.. -- Rob Clark
>> v3: rebase, missing padding in drm_event_atomic.. -- Rob Clark
>>
>> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>> ---
>>  drivers/gpu/drm/drm_crtc.c  | 159 ++++++++++++++++++++++++++++++++++++++++++++
>>  drivers/gpu/drm/drm_drv.c   |   1 +
>>  include/drm/drmP.h          |   6 ++
>>  include/drm/drm_crtc.h      |   2 +
>>  include/uapi/drm/drm.h      |  12 ++++
>>  include/uapi/drm/drm_mode.h |  16 +++++
>>  6 files changed, 196 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
>> index 09396a9..910e5c6 100644
>> --- a/drivers/gpu/drm/drm_crtc.c
>> +++ b/drivers/gpu/drm/drm_crtc.c
>> @@ -4338,3 +4338,162 @@ void drm_mode_config_cleanup(struct drm_device *dev)
>>       idr_destroy(&dev->mode_config.crtc_idr);
>>  }
>>  EXPORT_SYMBOL(drm_mode_config_cleanup);
>> +
>> +int drm_mode_atomic_ioctl(struct drm_device *dev,
>> +                       void *data, struct drm_file *file_priv)
>> +{
>> +     struct drm_mode_atomic *arg = data;
>> +     uint32_t __user *objs_ptr = (uint32_t __user *)(unsigned long)(arg->objs_ptr);
>> +     uint32_t __user *count_props_ptr = (uint32_t __user *)(unsigned long)(arg->count_props_ptr);
>> +     uint32_t __user *props_ptr = (uint32_t __user *)(unsigned long)(arg->props_ptr);
>> +     uint64_t __user *prop_values_ptr = (uint64_t __user *)(unsigned long)(arg->prop_values_ptr);
>> +     uint64_t __user *blob_values_ptr = (uint64_t __user *)(unsigned long)(arg->blob_values_ptr);
>> +     unsigned int copied_objs = 0;
>> +     unsigned int copied_props = 0;
>> +     unsigned int copied_blobs = 0;
>> +     void *state;
>> +     int ret = 0;
>> +     unsigned int i, j;
>> +
>> +     if (arg->flags & ~(DRM_MODE_ATOMIC_TEST_ONLY |
>> +                     DRM_MODE_ATOMIC_EVENT | DRM_MODE_ATOMIC_NONBLOCK))
>> +             return -EINVAL;
>> +
>> +     /* can't test and expect an event at the same time. */
>> +     if ((arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) &&
>> +                     (arg->flags & DRM_MODE_ATOMIC_EVENT))
>> +             return -EINVAL;
>> +
>> +     mutex_lock(&dev->mode_config.mutex);
>
> I'm pretty sure I had a version w/ fixed locking...
>
> git://gitorious.org/vsyrjala/linux.git rebased_drm_atomic_24

oh, hmm.. actually the locking should no longer be in the ioctl fxn,
but should be pushed down to the commit.  looks like I missed this.  I
need to dig up some actual test code for atomic ioctl ;-)

>> +
>> +     state = dev->driver->atomic_begin(dev, arg->flags);
>> +     if (IS_ERR(state)) {
>> +             ret = PTR_ERR(state);
>> +             goto unlock;
>> +     }
>> +
>> +     for (i = 0; i < arg->count_objs; i++) {
>> +             uint32_t obj_id, count_props;
>> +             struct drm_mode_object *obj;
>> +
>> +             if (get_user(obj_id, objs_ptr + copied_objs)) {
>> +                     ret = -EFAULT;
>> +                     goto out;
>> +             }
>> +
>> +             obj = drm_mode_object_find(dev, obj_id, DRM_MODE_OBJECT_ANY);
>> +             if (!obj || !obj->properties) {
>> +                     ret = -ENOENT;
>> +                     goto out;
>> +             }
>> +
>> +             if (arg->flags & DRM_MODE_ATOMIC_EVENT) {
>> +                     // XXX create atomic event instead..
>
> Some people are apparently more comfortable with a per-crtc event
> rather than the per-obj events I added. So I think we might want
> both in the end.

yeah, sorting out events is a bit 'TODO' at the moment.  I do kind of
like per-crtc event.. it seems easier to implement and I'm not really
sure what finer event granularity buys us.

BR,
-R

>> +                     struct drm_pending_vblank_event *e =
>> +                             create_vblank_event(dev, file_priv, arg->user_data);
>> +                     if (!e) {
>> +                             ret = -ENOMEM;
>> +                             goto out;
>> +                     }
>> +                     ret = dev->driver->atomic_set_event(dev, state, obj, e);
>> +                     if (ret) {
>> +                             destroy_vblank_event(dev, file_priv, e);
>> +                             goto out;
>> +                     }
>> +             }
>> +
>> +             if (get_user(count_props, count_props_ptr + copied_objs)) {
>> +                     ret = -EFAULT;
>> +                     goto out;
>> +             }
>> +
>> +             copied_objs++;
>> +
>> +             for (j = 0; j < count_props; j++) {
>> +                     uint32_t prop_id;
>> +                     uint64_t prop_value;
>> +                     struct drm_mode_object *prop_obj;
>> +                     struct drm_property *prop;
>> +                     void *blob_data = NULL;
>> +
>> +                     if (get_user(prop_id, props_ptr + copied_props)) {
>> +                             ret = -EFAULT;
>> +                             goto out;
>> +                     }
>> +
>> +                     if (!object_has_prop(obj, prop_id)) {
>> +                             ret = -EINVAL;
>> +                             goto out;
>> +                     }
>> +
>> +                     prop_obj = drm_mode_object_find(dev, prop_id,
>> +                                     DRM_MODE_OBJECT_PROPERTY);
>> +                     if (!prop_obj) {
>> +                             ret = -ENOENT;
>> +                             goto out;
>> +                     }
>> +                     prop = obj_to_property(prop_obj);
>> +
>> +                     if (get_user(prop_value, prop_values_ptr + copied_props)) {
>> +                             ret = -EFAULT;
>> +                             goto out;
>> +                     }
>> +
>> +                     if (!drm_property_change_is_valid(prop, prop_value)) {
>> +                             ret = -EINVAL;
>> +                             goto out;
>> +                     }
>> +
>> +                     if ((prop->flags & DRM_MODE_PROP_BLOB) && prop_value) {
>> +                             uint64_t blob_ptr;
>> +
>> +                             if (get_user(blob_ptr, blob_values_ptr + copied_blobs)) {
>> +                                     ret = -EFAULT;
>> +                                     goto out;
>> +                             }
>> +
>> +                             blob_data = kmalloc(prop_value, GFP_KERNEL);
>> +                             if (!blob_data) {
>> +                                     ret = -ENOMEM;
>> +                                     goto out;
>> +                             }
>> +
>> +                             if (copy_from_user(blob_data, (void __user *)(unsigned long)blob_ptr, prop_value)) {
>> +                                     kfree(blob_data);
>> +                                     ret = -EFAULT;
>> +                                     goto out;
>> +                             }
>> +                     }
>> +
>> +                     /* User space sends the blob pointer even if we
>> +                      * don't use it (length==0).
>> +                      */
>> +                     if (prop->flags & DRM_MODE_PROP_BLOB)
>> +                             copied_blobs++;
>> +
>> +                     /* The driver will be in charge of blob_data from now on. */
>> +                     ret = drm_mode_set_obj_prop(obj, state, prop,
>> +                                     prop_value, blob_data);
>> +                     if (ret)
>> +                             goto out;
>> +
>> +                     copied_props++;
>> +             }
>> +     }
>> +
>> +     ret = dev->driver->atomic_check(dev, state);
>> +     if (ret)
>> +             goto out;
>> +
>> +     if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY)
>> +             goto out;
>> +
>> +     ret = dev->driver->atomic_commit(dev, state);
>> +
>> + out:
>> +     dev->driver->atomic_end(dev, state);
>> + unlock:
>> +     mutex_unlock(&dev->mode_config.mutex);
>> +
>> +     return ret;
>> +}
>> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
>> index e572dd2..43e04ae 100644
>> --- a/drivers/gpu/drm/drm_drv.c
>> +++ b/drivers/gpu/drm/drm_drv.c
>> @@ -166,6 +166,7 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
>>       DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_GETPROPERTIES, drm_mode_obj_get_properties_ioctl, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
>>       DRM_IOCTL_DEF(DRM_IOCTL_MODE_OBJ_SETPROPERTY, drm_mode_obj_set_property_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
>>       DRM_IOCTL_DEF(DRM_IOCTL_MODE_CURSOR2, drm_mode_cursor2_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
>> +     DRM_IOCTL_DEF(DRM_IOCTL_MODE_ATOMIC, drm_mode_atomic_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
>>  };
>>
>>  #define DRM_CORE_IOCTL_COUNT ARRAY_SIZE( drm_ioctls )
>> diff --git a/include/drm/drmP.h b/include/drm/drmP.h
>> index 4c3de22..f282733 100644
>> --- a/include/drm/drmP.h
>> +++ b/include/drm/drmP.h
>> @@ -1158,6 +1158,12 @@ struct drm_pending_vblank_event {
>>       struct drm_event_vblank event;
>>  };
>>
>> +struct drm_pending_atomic_event {
>> +     struct drm_pending_event base;
>> +     int pipe;
>> +     struct drm_event_atomic event;
>> +};
>> +
>>  /**
>>   * DRM device structure. This structure represent a complete card that
>>   * may contain multiple heads.
>> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
>> index 86a5a00..fa3956e 100644
>> --- a/include/drm/drm_crtc.h
>> +++ b/include/drm/drm_crtc.h
>> @@ -1313,6 +1313,8 @@ extern int drm_mode_obj_get_properties_ioctl(struct drm_device *dev, void *data,
>>                                            struct drm_file *file_priv);
>>  extern int drm_mode_obj_set_property_ioctl(struct drm_device *dev, void *data,
>>                                          struct drm_file *file_priv);
>> +extern int drm_mode_atomic_ioctl(struct drm_device *dev,
>> +                              void *data, struct drm_file *file_priv);
>>
>>  extern void drm_fb_get_bpp_depth(uint32_t format, unsigned int *depth,
>>                                int *bpp);
>> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
>> index ece8678..efb1461 100644
>> --- a/include/uapi/drm/drm.h
>> +++ b/include/uapi/drm/drm.h
>> @@ -733,6 +733,7 @@ struct drm_prime_handle {
>>  #define DRM_IOCTL_MODE_OBJ_GETPROPERTIES     DRM_IOWR(0xB9, struct drm_mode_obj_get_properties)
>>  #define DRM_IOCTL_MODE_OBJ_SETPROPERTY       DRM_IOWR(0xBA, struct drm_mode_obj_set_property)
>>  #define DRM_IOCTL_MODE_CURSOR2               DRM_IOWR(0xBB, struct drm_mode_cursor2)
>> +#define DRM_IOCTL_MODE_ATOMIC                DRM_IOWR(0xBC, struct drm_mode_atomic)
>>
>>  /**
>>   * Device specific ioctls should only be in their respective headers
>> @@ -774,6 +775,17 @@ struct drm_event_vblank {
>>       __u32 reserved;
>>  };
>>
>> +struct drm_event_atomic {
>> +     struct drm_event base;
>> +     __u64 user_data;
>> +     __u32 tv_sec;
>> +     __u32 tv_usec;
>> +     __u32 sequence;
>> +     __u32 obj_id;
>> +     __u32 old_fb_id;
>> +     __u32 reserved;
>> +};
>> +
>>  #define DRM_CAP_DUMB_BUFFER 0x1
>>  #define DRM_CAP_VBLANK_HIGH_CRTC 0x2
>>  #define DRM_CAP_DUMB_PREFERRED_DEPTH 0x3
>> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
>> index 6d4f089..03a473c 100644
>> --- a/include/uapi/drm/drm_mode.h
>> +++ b/include/uapi/drm/drm_mode.h
>> @@ -489,4 +489,20 @@ struct drm_mode_destroy_dumb {
>>       uint32_t handle;
>>  };
>>
>> +#define DRM_MODE_ATOMIC_TEST_ONLY (1<<0)
>> +#define DRM_MODE_ATOMIC_EVENT (1<<1)
>> +#define DRM_MODE_ATOMIC_NONBLOCK (1<<2)
>> +
>> +/* FIXME come up with some sane error reporting mechanism? */
>> +struct drm_mode_atomic {
>> +     __u32 flags;
>> +     __u32 count_objs;
>> +     __u64 objs_ptr;
>> +     __u64 count_props_ptr;
>> +     __u64 props_ptr;
>> +     __u64 prop_values_ptr;
>> +     __u64 blob_values_ptr;
>> +     __u64 user_data;
>> +};
>> +
>>  #endif
>> --
>> 1.8.3.1
>
> --
> Ville Syrjälä
> Intel OTC


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