linux/drivers/gpu/drm/drm_blend.c
Michal Hocko 0ee931c4e3 mm: treewide: remove GFP_TEMPORARY allocation flag
GFP_TEMPORARY was introduced by commit e12ba74d8f ("Group short-lived
and reclaimable kernel allocations") along with __GFP_RECLAIMABLE.  It's
primary motivation was to allow users to tell that an allocation is
short lived and so the allocator can try to place such allocations close
together and prevent long term fragmentation.  As much as this sounds
like a reasonable semantic it becomes much less clear when to use the
highlevel GFP_TEMPORARY allocation flag.  How long is temporary? Can the
context holding that memory sleep? Can it take locks? It seems there is
no good answer for those questions.

The current implementation of GFP_TEMPORARY is basically GFP_KERNEL |
__GFP_RECLAIMABLE which in itself is tricky because basically none of
the existing caller provide a way to reclaim the allocated memory.  So
this is rather misleading and hard to evaluate for any benefits.

I have checked some random users and none of them has added the flag
with a specific justification.  I suspect most of them just copied from
other existing users and others just thought it might be a good idea to
use without any measuring.  This suggests that GFP_TEMPORARY just
motivates for cargo cult usage without any reasoning.

I believe that our gfp flags are quite complex already and especially
those with highlevel semantic should be clearly defined to prevent from
confusion and abuse.  Therefore I propose dropping GFP_TEMPORARY and
replace all existing users to simply use GFP_KERNEL.  Please note that
SLAB users with shrinkers will still get __GFP_RECLAIMABLE heuristic and
so they will be placed properly for memory fragmentation prevention.

I can see reasons we might want some gfp flag to reflect shorterm
allocations but I propose starting from a clear semantic definition and
only then add users with proper justification.

This was been brought up before LSF this year by Matthew [1] and it
turned out that GFP_TEMPORARY really doesn't have a clear semantic.  It
seems to be a heuristic without any measured advantage for most (if not
all) its current users.  The follow up discussion has revealed that
opinions on what might be temporary allocation differ a lot between
developers.  So rather than trying to tweak existing users into a
semantic which they haven't expected I propose to simply remove the flag
and start from scratch if we really need a semantic for short term
allocations.

[1] http://lkml.kernel.org/r/20170118054945.GD18349@bombadil.infradead.org

[akpm@linux-foundation.org: fix typo]
[akpm@linux-foundation.org: coding-style fixes]
[sfr@canb.auug.org.au: drm/i915: fix up]
  Link: http://lkml.kernel.org/r/20170816144703.378d4f4d@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170728091904.14627-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-13 18:53:16 -07:00

408 lines
14 KiB
C

/*
* Copyright (C) 2016 Samsung Electronics Co.Ltd
* Authors:
* Marek Szyprowski <m.szyprowski@samsung.com>
*
* DRM core plane blending related functions
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that copyright
* notice and this permission notice appear in supporting documentation, and
* that the name of the copyright holders not be used in advertising or
* publicity pertaining to distribution of the software without specific,
* written prior permission. The copyright holders make no representations
* about the suitability of this software for any purpose. It is provided "as
* is" without express or implied warranty.
*
* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
* OF THIS SOFTWARE.
*/
#include <drm/drmP.h>
#include <drm/drm_atomic.h>
#include <drm/drm_blend.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include "drm_crtc_internal.h"
/**
* DOC: overview
*
* The basic plane composition model supported by standard plane properties only
* has a source rectangle (in logical pixels within the &drm_framebuffer), with
* sub-pixel accuracy, which is scaled up to a pixel-aligned destination
* rectangle in the visible area of a &drm_crtc. The visible area of a CRTC is
* defined by the horizontal and vertical visible pixels (stored in @hdisplay
* and @vdisplay) of the requested mode (stored in &drm_crtc_state.mode). These
* two rectangles are both stored in the &drm_plane_state.
*
* For the atomic ioctl the following standard (atomic) properties on the plane object
* encode the basic plane composition model:
*
* SRC_X:
* X coordinate offset for the source rectangle within the
* &drm_framebuffer, in 16.16 fixed point. Must be positive.
* SRC_Y:
* Y coordinate offset for the source rectangle within the
* &drm_framebuffer, in 16.16 fixed point. Must be positive.
* SRC_W:
* Width for the source rectangle within the &drm_framebuffer, in 16.16
* fixed point. SRC_X plus SRC_W must be within the width of the source
* framebuffer. Must be positive.
* SRC_H:
* Height for the source rectangle within the &drm_framebuffer, in 16.16
* fixed point. SRC_Y plus SRC_H must be within the height of the source
* framebuffer. Must be positive.
* CRTC_X:
* X coordinate offset for the destination rectangle. Can be negative.
* CRTC_Y:
* Y coordinate offset for the destination rectangle. Can be negative.
* CRTC_W:
* Width for the destination rectangle. CRTC_X plus CRTC_W can extend past
* the currently visible horizontal area of the &drm_crtc.
* CRTC_H:
* Height for the destination rectangle. CRTC_Y plus CRTC_H can extend past
* the currently visible vertical area of the &drm_crtc.
* FB_ID:
* Mode object ID of the &drm_framebuffer this plane should scan out.
* CRTC_ID:
* Mode object ID of the &drm_crtc this plane should be connected to.
*
* Note that the source rectangle must fully lie within the bounds of the
* &drm_framebuffer. The destination rectangle can lie outside of the visible
* area of the current mode of the CRTC. It must be apprpriately clipped by the
* driver, which can be done by calling drm_plane_helper_check_update(). Drivers
* are also allowed to round the subpixel sampling positions appropriately, but
* only to the next full pixel. No pixel outside of the source rectangle may
* ever be sampled, which is important when applying more sophisticated
* filtering than just a bilinear one when scaling. The filtering mode when
* scaling is unspecified.
*
* On top of this basic transformation additional properties can be exposed by
* the driver:
*
* - Rotation is set up with drm_plane_create_rotation_property(). It adds a
* rotation and reflection step between the source and destination rectangles.
* Without this property the rectangle is only scaled, but not rotated or
* reflected.
*
* - Z position is set up with drm_plane_create_zpos_immutable_property() and
* drm_plane_create_zpos_property(). It controls the visibility of overlapping
* planes. Without this property the primary plane is always below the cursor
* plane, and ordering between all other planes is undefined.
*
* Note that all the property extensions described here apply either to the
* plane or the CRTC (e.g. for the background color, which currently is not
* exposed and assumed to be black).
*/
/**
* drm_plane_create_rotation_property - create a new rotation property
* @plane: drm plane
* @rotation: initial value of the rotation property
* @supported_rotations: bitmask of supported rotations and reflections
*
* This creates a new property with the selected support for transformations.
*
* Since a rotation by 180° degress is the same as reflecting both along the x
* and the y axis the rotation property is somewhat redundant. Drivers can use
* drm_rotation_simplify() to normalize values of this property.
*
* The property exposed to userspace is a bitmask property (see
* drm_property_create_bitmask()) called "rotation" and has the following
* bitmask enumaration values:
*
* DRM_MODE_ROTATE_0:
* "rotate-0"
* DRM_MODE_ROTATE_90:
* "rotate-90"
* DRM_MODE_ROTATE_180:
* "rotate-180"
* DRM_MODE_ROTATE_270:
* "rotate-270"
* DRM_MODE_REFLECT_X:
* "reflect-x"
* DRM_MODE_REFLECT_Y:
* "reflect-y"
*
* Rotation is the specified amount in degrees in counter clockwise direction,
* the X and Y axis are within the source rectangle, i.e. the X/Y axis before
* rotation. After reflection, the rotation is applied to the image sampled from
* the source rectangle, before scaling it to fit the destination rectangle.
*/
int drm_plane_create_rotation_property(struct drm_plane *plane,
unsigned int rotation,
unsigned int supported_rotations)
{
static const struct drm_prop_enum_list props[] = {
{ __builtin_ffs(DRM_MODE_ROTATE_0) - 1, "rotate-0" },
{ __builtin_ffs(DRM_MODE_ROTATE_90) - 1, "rotate-90" },
{ __builtin_ffs(DRM_MODE_ROTATE_180) - 1, "rotate-180" },
{ __builtin_ffs(DRM_MODE_ROTATE_270) - 1, "rotate-270" },
{ __builtin_ffs(DRM_MODE_REFLECT_X) - 1, "reflect-x" },
{ __builtin_ffs(DRM_MODE_REFLECT_Y) - 1, "reflect-y" },
};
struct drm_property *prop;
WARN_ON((supported_rotations & DRM_MODE_ROTATE_MASK) == 0);
WARN_ON(!is_power_of_2(rotation & DRM_MODE_ROTATE_MASK));
WARN_ON(rotation & ~supported_rotations);
prop = drm_property_create_bitmask(plane->dev, 0, "rotation",
props, ARRAY_SIZE(props),
supported_rotations);
if (!prop)
return -ENOMEM;
drm_object_attach_property(&plane->base, prop, rotation);
if (plane->state)
plane->state->rotation = rotation;
plane->rotation_property = prop;
return 0;
}
EXPORT_SYMBOL(drm_plane_create_rotation_property);
/**
* drm_rotation_simplify() - Try to simplify the rotation
* @rotation: Rotation to be simplified
* @supported_rotations: Supported rotations
*
* Attempt to simplify the rotation to a form that is supported.
* Eg. if the hardware supports everything except DRM_MODE_REFLECT_X
* one could call this function like this:
*
* drm_rotation_simplify(rotation, DRM_MODE_ROTATE_0 |
* DRM_MODE_ROTATE_90 | DRM_MODE_ROTATE_180 |
* DRM_MODE_ROTATE_270 | DRM_MODE_REFLECT_Y);
*
* to eliminate the DRM_MODE_ROTATE_X flag. Depending on what kind of
* transforms the hardware supports, this function may not
* be able to produce a supported transform, so the caller should
* check the result afterwards.
*/
unsigned int drm_rotation_simplify(unsigned int rotation,
unsigned int supported_rotations)
{
if (rotation & ~supported_rotations) {
rotation ^= DRM_MODE_REFLECT_X | DRM_MODE_REFLECT_Y;
rotation = (rotation & DRM_MODE_REFLECT_MASK) |
BIT((ffs(rotation & DRM_MODE_ROTATE_MASK) + 1)
% 4);
}
return rotation;
}
EXPORT_SYMBOL(drm_rotation_simplify);
/**
* drm_plane_create_zpos_property - create mutable zpos property
* @plane: drm plane
* @zpos: initial value of zpos property
* @min: minimal possible value of zpos property
* @max: maximal possible value of zpos property
*
* This function initializes generic mutable zpos property and enables support
* for it in drm core. Drivers can then attach this property to planes to enable
* support for configurable planes arrangement during blending operation.
* Once mutable zpos property has been enabled, the DRM core will automatically
* calculate &drm_plane_state.normalized_zpos values. Usually min should be set
* to 0 and max to maximal number of planes for given crtc - 1.
*
* If zpos of some planes cannot be changed (like fixed background or
* cursor/topmost planes), driver should adjust min/max values and assign those
* planes immutable zpos property with lower or higher values (for more
* information, see drm_plane_create_zpos_immutable_property() function). In such
* case driver should also assign proper initial zpos values for all planes in
* its plane_reset() callback, so the planes will be always sorted properly.
*
* See also drm_atomic_normalize_zpos().
*
* The property exposed to userspace is called "zpos".
*
* Returns:
* Zero on success, negative errno on failure.
*/
int drm_plane_create_zpos_property(struct drm_plane *plane,
unsigned int zpos,
unsigned int min, unsigned int max)
{
struct drm_property *prop;
prop = drm_property_create_range(plane->dev, 0, "zpos", min, max);
if (!prop)
return -ENOMEM;
drm_object_attach_property(&plane->base, prop, zpos);
plane->zpos_property = prop;
if (plane->state) {
plane->state->zpos = zpos;
plane->state->normalized_zpos = zpos;
}
return 0;
}
EXPORT_SYMBOL(drm_plane_create_zpos_property);
/**
* drm_plane_create_zpos_immutable_property - create immuttable zpos property
* @plane: drm plane
* @zpos: value of zpos property
*
* This function initializes generic immutable zpos property and enables
* support for it in drm core. Using this property driver lets userspace
* to get the arrangement of the planes for blending operation and notifies
* it that the hardware (or driver) doesn't support changing of the planes'
* order. For mutable zpos see drm_plane_create_zpos_property().
*
* The property exposed to userspace is called "zpos".
*
* Returns:
* Zero on success, negative errno on failure.
*/
int drm_plane_create_zpos_immutable_property(struct drm_plane *plane,
unsigned int zpos)
{
struct drm_property *prop;
prop = drm_property_create_range(plane->dev, DRM_MODE_PROP_IMMUTABLE,
"zpos", zpos, zpos);
if (!prop)
return -ENOMEM;
drm_object_attach_property(&plane->base, prop, zpos);
plane->zpos_property = prop;
if (plane->state) {
plane->state->zpos = zpos;
plane->state->normalized_zpos = zpos;
}
return 0;
}
EXPORT_SYMBOL(drm_plane_create_zpos_immutable_property);
static int drm_atomic_state_zpos_cmp(const void *a, const void *b)
{
const struct drm_plane_state *sa = *(struct drm_plane_state **)a;
const struct drm_plane_state *sb = *(struct drm_plane_state **)b;
if (sa->zpos != sb->zpos)
return sa->zpos - sb->zpos;
else
return sa->plane->base.id - sb->plane->base.id;
}
static int drm_atomic_helper_crtc_normalize_zpos(struct drm_crtc *crtc,
struct drm_crtc_state *crtc_state)
{
struct drm_atomic_state *state = crtc_state->state;
struct drm_device *dev = crtc->dev;
int total_planes = dev->mode_config.num_total_plane;
struct drm_plane_state **states;
struct drm_plane *plane;
int i, n = 0;
int ret = 0;
DRM_DEBUG_ATOMIC("[CRTC:%d:%s] calculating normalized zpos values\n",
crtc->base.id, crtc->name);
states = kmalloc_array(total_planes, sizeof(*states), GFP_KERNEL);
if (!states)
return -ENOMEM;
/*
* Normalization process might create new states for planes which
* normalized_zpos has to be recalculated.
*/
drm_for_each_plane_mask(plane, dev, crtc_state->plane_mask) {
struct drm_plane_state *plane_state =
drm_atomic_get_plane_state(state, plane);
if (IS_ERR(plane_state)) {
ret = PTR_ERR(plane_state);
goto done;
}
states[n++] = plane_state;
DRM_DEBUG_ATOMIC("[PLANE:%d:%s] processing zpos value %d\n",
plane->base.id, plane->name,
plane_state->zpos);
}
sort(states, n, sizeof(*states), drm_atomic_state_zpos_cmp, NULL);
for (i = 0; i < n; i++) {
plane = states[i]->plane;
states[i]->normalized_zpos = i;
DRM_DEBUG_ATOMIC("[PLANE:%d:%s] normalized zpos value %d\n",
plane->base.id, plane->name, i);
}
crtc_state->zpos_changed = true;
done:
kfree(states);
return ret;
}
/**
* drm_atomic_normalize_zpos - calculate normalized zpos values for all crtcs
* @dev: DRM device
* @state: atomic state of DRM device
*
* This function calculates normalized zpos value for all modified planes in
* the provided atomic state of DRM device.
*
* For every CRTC this function checks new states of all planes assigned to
* it and calculates normalized zpos value for these planes. Planes are compared
* first by their zpos values, then by plane id (if zpos is equal). The plane
* with lowest zpos value is at the bottom. The &drm_plane_state.normalized_zpos
* is then filled with unique values from 0 to number of active planes in crtc
* minus one.
*
* RETURNS
* Zero for success or -errno
*/
int drm_atomic_normalize_zpos(struct drm_device *dev,
struct drm_atomic_state *state)
{
struct drm_crtc *crtc;
struct drm_crtc_state *old_crtc_state, *new_crtc_state;
struct drm_plane *plane;
struct drm_plane_state *old_plane_state, *new_plane_state;
int i, ret = 0;
for_each_oldnew_plane_in_state(state, plane, old_plane_state, new_plane_state, i) {
crtc = new_plane_state->crtc;
if (!crtc)
continue;
if (old_plane_state->zpos != new_plane_state->zpos) {
new_crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
new_crtc_state->zpos_changed = true;
}
}
for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
if (old_crtc_state->plane_mask != new_crtc_state->plane_mask ||
new_crtc_state->zpos_changed) {
ret = drm_atomic_helper_crtc_normalize_zpos(crtc,
new_crtc_state);
if (ret)
return ret;
}
}
return 0;
}
EXPORT_SYMBOL(drm_atomic_normalize_zpos);