Keith,
This looks good to me too.
Keith
Keith Packard wrote:
> commit 9856a00ee5e6de30ba3040749583b2eafdf2dfc1
> Author: Keith Packard <[EMAIL PROTECTED]>
> Date: Sun Dec 16 22:00:45 2007 -0800
>
> Change drm_bo_type_dc to drm_bo_type_device and comment usage of this
> value.
>
> I couldn't figure out what drm_bo_type_dc was for; Dave Airlie finally
> clued
> me in that it was the 'normal' buffer objects with kernel allocated pages
> that could be mmapped from the drm device file.
>
> I thought that 'drm_bo_type_device' was a more descriptive name.
>
> I also added a bunch of comments describing the use of the type enum
> values and
> the functions that use them.
>
> diff --git a/linux-core/drm_bo.c b/linux-core/drm_bo.c
> index 171c074..df10e12 100644
> --- a/linux-core/drm_bo.c
> +++ b/linux-core/drm_bo.c
> @@ -146,7 +146,7 @@ static int drm_bo_add_ttm(struct drm_buffer_object *bo)
> page_flags |= DRM_TTM_PAGE_WRITE;
>
> switch (bo->type) {
> - case drm_bo_type_dc:
> + case drm_bo_type_device:
> case drm_bo_type_kernel:
> bo->ttm = drm_ttm_create(dev, bo->num_pages << PAGE_SHIFT,
> page_flags, dev->bm.dummy_read_page);
> @@ -1155,7 +1155,12 @@ static void drm_bo_fill_rep_arg(struct
> drm_buffer_object *bo,
> rep->size = bo->num_pages * PAGE_SIZE;
> rep->offset = bo->offset;
>
> - if (bo->type == drm_bo_type_dc)
> + /*
> + * drm_bo_type_device buffers have user-visible
> + * handles which can be used to share across
> + * processes. Hand that back to the application
> + */
> + if (bo->type == drm_bo_type_device)
> rep->arg_handle = bo->map_list.user_token;
> else
> rep->arg_handle = 0;
> @@ -1786,7 +1791,12 @@ int drm_buffer_object_create(struct drm_device *dev,
> if (ret)
> goto out_err;
>
> - if (bo->type == drm_bo_type_dc) {
> + /*
> + * For drm_bo_type_device buffers, allocate
> + * address space from the device so that applications
> + * can mmap the buffer from there
> + */
> + if (bo->type == drm_bo_type_device) {
> mutex_lock(&dev->struct_mutex);
> ret = drm_bo_setup_vm_locked(bo);
> mutex_unlock(&dev->struct_mutex);
> @@ -1849,7 +1859,12 @@ int drm_bo_create_ioctl(struct drm_device *dev, void
> *data, struct drm_file *fil
> return -EINVAL;
> }
>
> - bo_type = (req->buffer_start) ? drm_bo_type_user : drm_bo_type_dc;
> + /*
> + * If the buffer creation request comes in with a starting address,
> + * that points at the desired user pages to map. Otherwise, create
> + * a drm_bo_type_device buffer, which uses pages allocated from the
> kernel
> + */
> + bo_type = (req->buffer_start) ? drm_bo_type_user : drm_bo_type_device;
>
> /*
> * User buffers cannot be shared
> @@ -2607,6 +2622,14 @@ void drm_bo_unmap_virtual(struct drm_buffer_object *bo)
> unmap_mapping_range(dev->dev_mapping, offset, holelen, 1);
> }
>
> +/**
> + * drm_bo_takedown_vm_locked:
> + *
> + * @bo: the buffer object to remove any drm device mapping
> + *
> + * Remove any associated vm mapping on the drm device node that
> + * would have been created for a drm_bo_type_device buffer
> + */
> static void drm_bo_takedown_vm_locked(struct drm_buffer_object *bo)
> {
> struct drm_map_list *list;
> @@ -2614,7 +2637,7 @@ static void drm_bo_takedown_vm_locked(struct
> drm_buffer_object *bo)
> struct drm_device *dev = bo->dev;
>
> DRM_ASSERT_LOCKED(&dev->struct_mutex);
> - if (bo->type != drm_bo_type_dc)
> + if (bo->type != drm_bo_type_device)
> return;
>
> list = &bo->map_list;
> @@ -2637,6 +2660,16 @@ static void drm_bo_takedown_vm_locked(struct
> drm_buffer_object *bo)
> drm_bo_usage_deref_locked(&bo);
> }
>
> +/**
> + * drm_bo_setup_vm_locked:
> + *
> + * @bo: the buffer to allocate address space for
> + *
> + * Allocate address space in the drm device so that applications
> + * can mmap the buffer and access the contents. This only
> + * applies to drm_bo_type_device objects as others are not
> + * placed in the drm device address space.
> + */
> static int drm_bo_setup_vm_locked(struct drm_buffer_object *bo)
> {
> struct drm_map_list *list = &bo->map_list;
> diff --git a/linux-core/drm_objects.h b/linux-core/drm_objects.h
> index 98421e4..a2d10b5 100644
> --- a/linux-core/drm_objects.h
> +++ b/linux-core/drm_objects.h
> @@ -404,9 +404,31 @@ struct drm_bo_mem_reg {
> };
>
> enum drm_bo_type {
> - drm_bo_type_dc,
> + /*
> + * drm_bo_type_device are 'normal' drm allocations,
> + * pages are allocated from within the kernel automatically
> + * and the objects can be mmap'd from the drm device. Each
> + * drm_bo_type_device object has a unique name which can be
> + * used by other processes to share access to the underlying
> + * buffer.
> + */
> + drm_bo_type_device,
> + /*
> + * drm_bo_type_user are buffers of pages that already exist
> + * in the process address space. They are more limited than
> + * drm_bo_type_device buffers in that they must always
> + * remain cached (as we assume the user pages are mapped cached),
> + * and they are not sharable to other processes through DRM
> + * (although, regular shared memory should still work fine).
> + */
> drm_bo_type_user,
> - drm_bo_type_kernel, /* for initial kernel allocations */
> + /*
> + * drm_bo_type_kernel are buffers that exist solely for use
> + * within the kernel. The pages cannot be mapped into the
> + * process. One obvious use would be for the ring
> + * buffer where user access would not (ideally) be required.
> + */
> + drm_bo_type_kernel,
> };
>
> struct drm_buffer_object {
>
>
>
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