Le 05/09/24 - 14:33, José Expósito a écrit : > Hi Louis, > > Thanks for appling the suggested changes. > > I added some minor style comments, but other than that patch looks > good to me. > > > Add documentation around vkms_output and its initialization. > > Add some documentation on pixel conversion functions. > > Update of outdated comments for pixel_write functions. > > > > Signed-off-by: Louis Chauvet <[email protected]> > > With the suggested changes, feel free to add: > Reviewed-by: José Expósito <[email protected]>
Thanks, the v4 is in your inbox! > > --- > > This series does not introduce functionnal changes, only some > > documentation and renaming to clarify the code. > > --- > > Changes in v3: > > - Merged > > https://lore.kernel.org/all/[email protected]/ > > as it also add documentation > > - Apply José's comments, sorry > > - Replace =1 by =BIT(0) for possible_crtc value > > - Link to v2: > > https://lore.kernel.org/r/[email protected] > > > > Changes in v2: > > - Dropped already applied patches > > - Dropped useless patch as its content is deleted later > > - Remove dependency on previous series > > - Apply Maíra's comments > > - Link to v1: > > https://lore.kernel.org/r/[email protected] > > --- > > drivers/gpu/drm/vkms/vkms_composer.c | 7 +++ > > drivers/gpu/drm/vkms/vkms_drv.h | 101 > > ++++++++++++++++++++++++++++++----- > > drivers/gpu/drm/vkms/vkms_formats.c | 62 +++++++++++++++++---- > > drivers/gpu/drm/vkms/vkms_output.c | 14 ++++- > > 4 files changed, 161 insertions(+), 23 deletions(-) > > > > > > --- > > base-commit: 84addde447fd9d713e101437db0d4924855eff4f > > change-id: 20240520-google-clarifications-dede8dcbe38a > > > > Best regards, > > > > diff --git a/drivers/gpu/drm/vkms/vkms_composer.c > > b/drivers/gpu/drm/vkms/vkms_composer.c > > index e7441b227b3c..57a5769fc994 100644 > > --- a/drivers/gpu/drm/vkms/vkms_composer.c > > +++ b/drivers/gpu/drm/vkms/vkms_composer.c > > @@ -189,6 +189,13 @@ static void blend(struct vkms_writeback_job *wb, > > > > size_t crtc_y_limit = crtc_state->base.crtc->mode.vdisplay; > > > > + /* > > + * The planes are composed line-by-line to avoid heavy memory usage. It > > is a necessary > > + * complexity to avoid poor blending performance. > > + * > > + * The function vkms_compose_row() is used to read a line, > > pixel-by-pixel, into the staging > > + * buffer. > > + */ > > for (size_t y = 0; y < crtc_y_limit; y++) { > > fill_background(&background_color, output_buffer); > > > > diff --git a/drivers/gpu/drm/vkms/vkms_drv.h > > b/drivers/gpu/drm/vkms/vkms_drv.h > > index 5e46ea5b96dc..12a11976f2fc 100644 > > --- a/drivers/gpu/drm/vkms/vkms_drv.h > > +++ b/drivers/gpu/drm/vkms/vkms_drv.h > > @@ -25,6 +25,17 @@ > > > > #define VKMS_LUT_SIZE 256 > > > > +/** > > + * struct vkms_frame_info - Structure to store the state of a frame > > + * > > + * @fb: backing drm framebuffer > > + * @src: source rectangle of this frame in the source framebuffer, stored > > in 16.16 fixed-point form > > + * @dst: destination rectangle in the crtc buffer, stored in whole pixel > > units > > + * @map: see drm_shadow_plane_state@data > > I think that the right format is "@drm_shadow_plane_state.data"? > https://docs.kernel.org/doc-guide/kernel-doc.html#nested-structs-unions > > > + * @rotation: rotation applied to the source. > > + * > > + * @src and @dst should have the same size modulo the rotation. > > + */ > > struct vkms_frame_info { > > struct drm_framebuffer *fb; > > struct drm_rect src, dst; > > @@ -52,9 +63,11 @@ struct vkms_writeback_job { > > }; > > > > /** > > - * vkms_plane_state - Driver specific plane state > > + * struct vkms_plane_state - Driver specific plane state > > * @base: base plane state > > * @frame_info: data required for composing computation > > + * @pixel_read: function to read a pixel in this plane. The creator of a > > struct vkms_plane_state > > + * must ensure that this pointer is valid > > */ > > struct vkms_plane_state { > > struct drm_shadow_plane_state base; > > @@ -73,29 +86,56 @@ struct vkms_color_lut { > > }; > > > > /** > > - * vkms_crtc_state - Driver specific CRTC state > > + * struct vkms_crtc_state - Driver specific CRTC state > > + * > > * @base: base CRTC state > > * @composer_work: work struct to compose and add CRC entries > > - * @n_frame_start: start frame number for computed CRC > > - * @n_frame_end: end frame number for computed CRC > > + * > > Sorry I missed this extra empty line in my previous review. > You can delete this extra "*". > > > + * @num_active_planes: Number of active planes > > + * @active_planes: List containing all the active planes (counted by > > + * @num_active_planes). They should be stored in z-order. > > + * @active_writeback: Current active writeback job > > + * @gamma_lut: Look up table for gamma used in this CRTC > > + * @crc_pending: Protected by @vkms_output.composer_lock, true when the > > frame CRC is not computed > > + * yet. Used by vblank to detect if the composer is too slow. > > + * @wb_pending: Protected by @vkms_output.composer_lock, true when a > > writeback frame is requested. > > + * @frame_start: Protected by @vkms_output.composer_lock, saves the frame > > number before the start > > + * of the composition process. > > + * @frame_end: Protected by @vkms_output.composer_lock, saves the last > > requested frame number. > > + * This is used to generate enough CRC entries when the composition > > worker is too slow. > > */ > > struct vkms_crtc_state { > > struct drm_crtc_state base; > > struct work_struct composer_work; > > > > int num_active_planes; > > - /* stack of active planes for crc computation, should be in z order */ > > struct vkms_plane_state **active_planes; > > struct vkms_writeback_job *active_writeback; > > struct vkms_color_lut gamma_lut; > > > > - /* below four are protected by vkms_output.composer_lock */ > > bool crc_pending; > > bool wb_pending; > > u64 frame_start; > > u64 frame_end; > > }; > > > > +/** > > + * struct vkms_output - Internal representation of all output components > > in VKMS > > + * > > + * @crtc: Base CRTC in DRM > > + * @encoder: DRM encoder used for this output > > + * @connector: DRM connector used for this output > > + * @wb_connecter: DRM writeback connector used for this output > > + * @vblank_hrtimer: Timer used to trigger the vblank > > + * @period_ns: vblank period, in nanoseconds, used to configure > > @vblank_hrtimer and to compute > > + * vblank timestamps > > + * @composer_workq: Ordered workqueue for @composer_state.composer_work. > > + * @lock: Lock used to protect concurrent access to the composer > > + * @composer_enabled: Protected by @lock, true when the VKMS composer is > > active (crc needed or > > + * writeback) > > + * @composer_state: Protected by @lock, current state of this VKMS output > > + * @composer_lock: Lock used internally to protect @composer_state members > > + */ > > struct vkms_output { > > struct drm_crtc crtc; > > struct drm_encoder encoder; > > @@ -103,28 +143,38 @@ struct vkms_output { > > struct drm_writeback_connector wb_connector; > > struct hrtimer vblank_hrtimer; > > ktime_t period_ns; > > - /* ordered wq for composer_work */ > > struct workqueue_struct *composer_workq; > > - /* protects concurrent access to composer */ > > spinlock_t lock; > > > > - /* protected by @lock */ > > bool composer_enabled; > > struct vkms_crtc_state *composer_state; > > > > spinlock_t composer_lock; > > }; > > > > -struct vkms_device; > > - > > +/** > > + * struct vkms_config - General configuration for VKMS driver > > + * > > + * @writeback: If true, a writeback buffer can be attached to the CRTC > > + * @cursor: If true, a cursor plane is created in the VKMS device > > + * @overlay: If true, NUM_OVERLAY_PLANES will be created for the VKMS > > device > > + * @dev: Used to store the current VKMS device. Only set when the device > > is instantiated. > > + */ > > struct vkms_config { > > bool writeback; > > bool cursor; > > bool overlay; > > - /* only set when instantiated */ > > struct vkms_device *dev; > > }; > > > > +/** > > + * struct vkms_device - Description of a VKMS device > > + * > > + * @drm - Base device in DRM > > + * @platform - Associated platform device > > + * @output - Configuration and sub-components of the VKMS device > > + * @config: Configuration used in this VKMS device > > + */ > > struct vkms_device { > > struct drm_device drm; > > struct platform_device *platform; > > @@ -132,6 +182,10 @@ struct vkms_device { > > const struct vkms_config *config; > > }; > > > > +/* > > + * The following helpers are used to convert a member of a struct into its > > parent. > > + */ > > + > > #define drm_crtc_to_vkms_output(target) \ > > container_of(target, struct vkms_output, crtc) > > > > @@ -144,12 +198,33 @@ struct vkms_device { > > #define to_vkms_plane_state(target)\ > > container_of(target, struct vkms_plane_state, base.base) > > > > -/* CRTC */ > > +/** > > + * vkms_crtc_init() - Initialize a CRTC for VKMS > > + * @dev: DRM device associated with the VKMS buffer > > + * @crtc: uninitialized CRTC device > > + * @primary: primary plane to attach to the CRTC > > + * @cursor plane to attach to the CRTC > > Missing ":" after "@cursor": > > * @cursor: cursor plane to attach to the CRTC > > > + */ > > int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc, > > struct drm_plane *primary, struct drm_plane *cursor); > > > > +/** > > + * vkms_output_init() - Initialize all sub-components needed for a VKMS > > device. > > + * > > + * @vkmsdev: VKMS device to initialize > > + * @index: CRTC which can be attached to the planes. The caller must > > ensure that > > + * @index is positive and less or equals to 31. > > + */ > > int vkms_output_init(struct vkms_device *vkmsdev, int index); > > > > +/** > > + * vkms_plane_init() - Initialize a plane > > + * > > + * @vkmsdev: VKMS device containing the plane > > + * @type: type of plane to initialize > > + * @possible_crtc_index: CRTC which can be attached to the plane. The > > caller must ensure that > > + * possible_crtc_index is positive and less or equals to 31. > > Should read: > > * @index: CRTC which can be attached to the plane. The caller must ensure > that > * @index is positive and less or equals to 31. > > > + */ > > struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev, > > enum drm_plane_type type, int index); > > > > diff --git a/drivers/gpu/drm/vkms/vkms_formats.c > > b/drivers/gpu/drm/vkms/vkms_formats.c > > index 040b7f113a3b..e8a5cc235ebb 100644 > > --- a/drivers/gpu/drm/vkms/vkms_formats.c > > +++ b/drivers/gpu/drm/vkms/vkms_formats.c > > @@ -9,24 +9,40 @@ > > > > #include "vkms_formats.h" > > > > +/** > > + * pixel_offset() - Get the offset of the pixel at coordinates x/y in the > > first plane > > + * > > + * @frame_info: Buffer metadata > > + * @x: The x coordinate of the wanted pixel in the buffer > > + * @y: The y coordinate of the wanted pixel in the buffer > > + * > > + * The caller must ensure that the framebuffer associated with this > > request uses a pixel format > > + * where block_h == block_w == 1. > > + * If this requirement is not fulfilled, the resulting offset can point to > > an other pixel or > > + * outside of the buffer. > > + */ > > static size_t pixel_offset(const struct vkms_frame_info *frame_info, int > > x, int y) > > { > > return frame_info->offset + (y * frame_info->pitch) > > + (x * frame_info->cpp); > > } > > > > -/* > > - * packed_pixels_addr - Get the pointer to pixel of a given pair of > > coordinates > > +/** > > + * packed_pixels_addr() - Get the pointer to the block containing the > > pixel at the given > > + * coordinates > > * > > * @frame_info: Buffer metadata > > - * @x: The x(width) coordinate of the 2D buffer > > - * @y: The y(Heigth) coordinate of the 2D buffer > > + * @x: The x (width) coordinate inside the plane > > + * @y: The y (height) coordinate inside the plane > > * > > * Takes the information stored in the frame_info, a pair of coordinates, > > and > > * returns the address of the first color channel. > > * This function assumes the channels are packed together, i.e. a color > > channel > > * comes immediately after another in the memory. And therefore, this > > function > > * doesn't work for YUV with chroma subsampling (e.g. YUV420 and NV21). > > + * > > + * The caller must ensure that the framebuffer associated with this > > request uses a pixel format > > + * where block_h == block_w == 1, otherwise the returned pointer can be > > outside the buffer. > > */ > > static void *packed_pixels_addr(const struct vkms_frame_info *frame_info, > > int x, int y) > > @@ -51,6 +67,13 @@ static int get_x_position(const struct vkms_frame_info > > *frame_info, int limit, i > > return x; > > } > > > > +/* > > + * The following functions take pixel data from the buffer and convert > > them to the format > > + * ARGB16161616 in @out_pixel. > > + * > > + * They are used in the vkms_compose_row() function to handle multiple > > formats. > > + */ > > + > > static void ARGB8888_to_argb_u16(u8 *src_pixels, struct pixel_argb_u16 > > *out_pixel) > > { > > /* > > @@ -143,12 +166,11 @@ void vkms_compose_row(struct line_buffer > > *stage_buffer, struct vkms_plane_state > > } > > > > /* > > - * The following functions take an line of argb_u16 pixels from the > > - * src_buffer, convert them to a specific format, and store them in the > > - * destination. > > + * The following functions take one &struct pixel_argb_u16 and convert it > > to a specific format. > > + * The result is stored in @dst_pixels. > > * > > - * They are used in the `compose_active_planes` to convert and store a line > > - * from the src_buffer to the writeback buffer. > > + * They are used in vkms_writeback_row() to convert and store a pixel from > > the src_buffer to > > + * the writeback buffer. > > */ > > static void argb_u16_to_ARGB8888(u8 *dst_pixels, struct pixel_argb_u16 > > *in_pixel) > > { > > @@ -214,6 +236,14 @@ static void argb_u16_to_RGB565(u8 *dst_pixels, struct > > pixel_argb_u16 *in_pixel) > > *pixels = cpu_to_le16(r << 11 | g << 5 | b); > > } > > > > +/** > > + * vkms_writeback_row() - Generic loop for all supported writeback format. > > It is executed just > > + * after the blending to write a line in the writeback buffer. > > + * > > + * @wb: Job where to insert the final image > > + * @src_buffer: Line to write > > + * @y: Row to write in the writeback buffer > > + */ > > void vkms_writeback_row(struct vkms_writeback_job *wb, > > const struct line_buffer *src_buffer, int y) > > { > > @@ -227,6 +257,13 @@ void vkms_writeback_row(struct vkms_writeback_job *wb, > > wb->pixel_write(dst_pixels, &in_pixels[x]); > > } > > > > +/** > > + * get_pixel_conversion_function() - Retrieve the correct read_pixel > > function for a specific > > + * format. The returned pointer is NULL for unsupported pixel formats. The > > caller must ensure that > > + * the pointer is valid before using it in a vkms_plane_state. > > + * > > + * @format: DRM_FORMAT_* value for which to obtain a conversion function > > (see [drm_fourcc.h]) > > + */ > > void *get_pixel_conversion_function(u32 format) > > { > > switch (format) { > > @@ -245,6 +282,13 @@ void *get_pixel_conversion_function(u32 format) > > } > > } > > > > +/** > > + * get_pixel_write_function() - Retrieve the correct write_pixel function > > for a specific format. > > + * The returned pointer is NULL for unsupported pixel formats. The caller > > must ensure that the > > + * pointer is valid before using it in a vkms_writeback_job. > > + * > > + * @format: DRM_FORMAT_* value for which to obtain a conversion function > > (see [drm_fourcc.h]) > > + */ > > void *get_pixel_write_function(u32 format) > > { > > switch (format) { > > diff --git a/drivers/gpu/drm/vkms/vkms_output.c > > b/drivers/gpu/drm/vkms/vkms_output.c > > index 5ce70dd946aa..56801e914208 100644 > > --- a/drivers/gpu/drm/vkms/vkms_output.c > > +++ b/drivers/gpu/drm/vkms/vkms_output.c > > @@ -21,6 +21,7 @@ static int vkms_conn_get_modes(struct drm_connector > > *connector) > > { > > int count; > > > > + /* Use the default modes list from DRM */ > > count = drm_add_modes_noedid(connector, XRES_MAX, YRES_MAX); > > drm_set_preferred_mode(connector, XRES_DEF, YRES_DEF); > > > > @@ -58,6 +59,12 @@ int vkms_output_init(struct vkms_device *vkmsdev, int > > index) > > int writeback; > > unsigned int n; > > > > + /* > > + * Initialize used plane. One primary plane is required to perform the > > composition. > > + * > > + * The overlay and cursor planes are not mandatory, but can be used to > > perform complex > > + * composition. > > + */ > > primary = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_PRIMARY, index); > > if (IS_ERR(primary)) > > return PTR_ERR(primary); > > @@ -76,6 +83,7 @@ int vkms_output_init(struct vkms_device *vkmsdev, int > > index) > > return PTR_ERR(cursor); > > } > > > > + /* [1]: Allocation of a CRTC, its index will be 1 */ > > It'd be great to clarify that BIT(0) == 1. Maybe? > > /* [1]: Allocation of a CRTC, its index will be BIT(0) = 1 */ Good catch, thanks! > > ret = vkms_crtc_init(dev, crtc, &primary->base, &cursor->base); > > if (ret) > > return ret; > > @@ -95,7 +103,11 @@ int vkms_output_init(struct vkms_device *vkmsdev, int > > index) > > DRM_ERROR("Failed to init encoder\n"); > > goto err_encoder; > > } > > - encoder->possible_crtcs = 1; > > + /* > > + * This is a hardcoded value to select crtc for the encoder. > > + * 1 here designate the first registered CRTC, the one allocated in [1] > > BIT(0) here designate the first... > > > + */ > > + encoder->possible_crtcs = BIT(0); > > > > ret = drm_connector_attach_encoder(connector, encoder); > > if (ret) {
