From patchwork Fri Aug 2 16:09:48 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Louis Chauvet X-Patchwork-Id: 13751774 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 39E03C3DA4A for ; Fri, 2 Aug 2024 16:10:14 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A45AA10E1A0; Fri, 2 Aug 2024 16:10:12 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=bootlin.com header.i=@bootlin.com header.b="GPx6p2KG"; dkim-atps=neutral Received: from relay5-d.mail.gandi.net (relay5-d.mail.gandi.net [217.70.183.197]) by gabe.freedesktop.org (Postfix) with ESMTPS id C941610E1A0 for ; Fri, 2 Aug 2024 16:10:11 +0000 (UTC) Received: by mail.gandi.net (Postfix) with ESMTPSA id BEEAB1C0005; Fri, 2 Aug 2024 16:10:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1722615010; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=OT45nvD0guqL+pxb0T1xTZXZv1MtSNJpc5aMecbORv0=; b=GPx6p2KGYNVuLfT96VKiBlnhhD3pDIc02aXiehIv4AKZc0CFtZi/o780Zr44z/8Cb9u2H+ d6NUPRMcbftnAhGont+5f+dkjV5RM8BI+s8FBVf1iW6IYtmXffTo1PVoqvf9ruemEe62CP LW5qTuiiwt0GEVFh9cfBiomThZpWyVxQFz6OqbwijVGUWHy60oi+CEtSj8TcfyhIYDCZu1 lt0H0bFL3sIdX4FPWDciyGeDe9koXFIvkwAnkHpKDHfQbvN9M8FABKhmNuUOXYRqOzeP9p P539oLyyFgzDv/qGF8PbxfLqPxDd1jEuSb8edlwisjmzRQAghY94PtN0AQ4+Dw== From: Louis Chauvet Date: Fri, 02 Aug 2024 18:09:48 +0200 Subject: [PATCH v9 03/17] drm/vkms: write/update the documentation for pixel conversion and pixel write functions MIME-Version: 1.0 Message-Id: <20240802-yuv-v9-3-08a706669e16@bootlin.com> References: <20240802-yuv-v9-0-08a706669e16@bootlin.com> In-Reply-To: <20240802-yuv-v9-0-08a706669e16@bootlin.com> To: Rodrigo Siqueira , Melissa Wen , =?utf-8?q?Ma=C3=ADra_Canal?= , Haneen Mohammed , Daniel Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Jonathan Corbet , rdunlap@infradead.org, arthurgrillo@riseup.net, pekka.paalanen@haloniitty.fi Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, jeremie.dautheribes@bootlin.com, miquel.raynal@bootlin.com, thomas.petazzoni@bootlin.com, seanpaul@google.com, marcheu@google.com, nicolejadeyee@google.com, Louis Chauvet , Pekka Paalanen X-Mailer: b4 0.14-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=7624; i=louis.chauvet@bootlin.com; h=from:subject:message-id; bh=MpVGFMROKpSyH5wkUctDE2WqOX1QrVwLTS+CMhEg1gk=; b=owEBbQKS/ZANAwAIASCtLsZbECziAcsmYgBmrQTadQtQ/+hktcrATxE/JTHJdgsuUvGQD5bZ4 AN5uBN3usKJAjMEAAEIAB0WIQRPj7g/vng8MQxQWQQgrS7GWxAs4gUCZq0E2gAKCRAgrS7GWxAs 4surD/9uhNjhWQiG0/6PV8A0/5k1r2VZM19Bcf52yHCgxuwBSZJnxUuQYPwZ76zeObWTLGGx4Ss INYedxKlQYY9zYY0NM7f5XukVRY4TPqN5qCvMwTczS6djGwexn6UKThtMVaFz5vdfoU1nzwQ3So 8/N42qpfec48zAJmV0NVTgza/rGX9u/rIp6NaZKORZXPwKObSCUCAmS+D1UPYcNVT8U8g1j7vSo 7yBsQcQQ2G1x8C1kZkTzqhUaOCwUAYV7LZpEBqkEQiYKUKQsj6xKZn5JL1bhcer+8/8oHjIC7eu U2MzcEN4XfKuUWpoOE5Jl3dxh1OAreUPqraqpINLnCjpFLwp3QQqPC8nrQHtebQI3P2iGu5hSEZ fyWqIgCJKTfZ1d7TKEa4q7MbAh+JrNVqmqsbehI/3HRV2axzb3N8tJRbBECMBYZeaqHN5KRi8hG /c5qs2Q26EYwjQgXneZTrqhFLyCXoF9y9fJ1mllGkjDCF0adXPczXk56wazaCx/gMslc0I+zBUm hA/oGawVd08CBN5N0sNNKM/Rkb0BmIyKe0e+n9ICAbNkAe3PYOyTa+gnBqoKfq11b0dDoBjlNq6 qKrLMKwJib0aUL45DUQX84S/eBCOsOdTswyHod+kwCDtr/wQlG8rDV9jjCIvUqWIhsVIQiDQOVI oB/HPh5xVrcoKLQ== X-Developer-Key: i=louis.chauvet@bootlin.com; a=openpgp; fpr=8B7104AE9A272D6693F527F2EC1883F55E0B40A5 X-GND-Sasl: louis.chauvet@bootlin.com X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Add some documentation on pixel conversion functions. Update of outdated comments for pixel_write functions. Signed-off-by: Louis Chauvet Acked-by: Pekka Paalanen --- drivers/gpu/drm/vkms/vkms_composer.c | 7 ++++ drivers/gpu/drm/vkms/vkms_drv.h | 15 ++++++++- drivers/gpu/drm/vkms/vkms_formats.c | 62 ++++++++++++++++++++++++++++++------ 3 files changed, 74 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c index c6d9b4a65809..931e214b225c 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 8ac320564334..d6851f1f9c38 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 + * @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; @@ -49,9 +60,11 @@ 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; diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c index d597c48452ac..7dc20d069c99 100644 --- a/drivers/gpu/drm/vkms/vkms_formats.c +++ b/drivers/gpu/drm/vkms/vkms_formats.c @@ -9,6 +9,18 @@ #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) { struct drm_framebuffer *fb = frame_info->fb; @@ -16,18 +28,22 @@ static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int return fb->offsets[0] + (y * fb->pitches[0]) + (x * fb->format->cpp[0]); } -/* - * 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) @@ -52,6 +68,13 @@ 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) { /* @@ -144,12 +167,11 @@ 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) { @@ -215,6 +237,14 @@ 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) { @@ -228,6 +258,13 @@ 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) { @@ -246,6 +283,13 @@ 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) {