From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2314632ED30 for ; Tue, 2 Sep 2025 13:36:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756820210; cv=none; b=Y7X/qGGiIRutSUIdOam/e9mgoAFxBX1DqWumvUwJFT6WdOqawnLO5gqtPOVDbQlwAPM/CJOY1PrwA1C00FQX0bb4Xh+Adg2MNA7YIw+cN21jbN8IoIMDKjtcehnpdK4L15W2dXefRepvI+TZ/7E7TQ69WjoCkytCd/1P5bQkaPc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756820210; c=relaxed/simple; bh=+O16tDhDhrBpLyMgsU885nrQA5KR/KrCl+HJfM6/ItA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gRLGr0GqNFTzs0BRw4+CjTEDMgnoQnZ4RYI3Dzwz5exB9k2+4Kun9sb96WEmoXvslIv9h7Bqdf5vo5gdHTwsRZ3Y8SYxJLPNHYlvjT0BSgajgKG739lxoFBtknZQ7aDfhWwmxMtf6GlPDPuVAD8oFg4RaHqD4YUGs94bmbHiKBs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=ejdpA3L6; arc=none smtp.client-ip=198.175.65.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="ejdpA3L6" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1756820208; x=1788356208; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=+O16tDhDhrBpLyMgsU885nrQA5KR/KrCl+HJfM6/ItA=; b=ejdpA3L6RxyaDxImQEZ/wVsMJAT0mC58tWxd9E4GTGtNovqL554RqMs/ 9iSOEx6OobdHK8v9SRaA3n+sxztSTMXxH9eotiL4K6G5Sqa05TXuvNe/V uhgOPt2dPR44Teys3Svw8HBMYN9R6audCnYPhebSrqi1MXw2t2NFrAzdF CZj+shjnEEknZroIYJo4r11jhfZVsJ0Y9BfoOR/9/OrB7L2ea8UEeY1Bk hVkDyH3HFCQVDhDyYej7nVmZkX2+soXna5AkMEByMy/uTPrivjk5jC+FZ CUNyy/bsgJnXItVmcYDtLIMAvzb/XuarvzWnU8FD1EPzmWsX04LjAZNvf w==; X-CSE-ConnectionGUID: gahppeebTS6Ft7l+odCzyQ== X-CSE-MsgGUID: 1+820xRqRfCQK0XAWM6+Wg== X-IronPort-AV: E=McAfee;i="6800,10657,11541"; a="62736793" X-IronPort-AV: E=Sophos;i="6.18,230,1751266800"; d="scan'208";a="62736793" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Sep 2025 06:36:47 -0700 X-CSE-ConnectionGUID: 8YzlxvkSQIC3enT5Sui24w== X-CSE-MsgGUID: 5KRLd1wDT0iPdDWuEkyafw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.18,230,1751266800"; d="scan'208";a="176588402" Received: from fpallare-mobl4.ger.corp.intel.com (HELO stinkbox) ([10.245.245.118]) by orviesa005.jf.intel.com with SMTP; 02 Sep 2025 06:36:42 -0700 Received: by stinkbox (sSMTP sendmail emulation); Tue, 02 Sep 2025 16:36:40 +0300 Date: Tue, 2 Sep 2025 16:36:40 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Cristian Ciocaltea Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Sandy Huang , Heiko =?iso-8859-1?Q?St=FCbner?= , Andy Yan , kernel@collabora.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, Matt Roper Subject: Re: [PATCH 1/2] drm: Add CRTC background color property Message-ID: References: <20250902-rk3588-bgcolor-v1-0-fd97df91d89f@collabora.com> <20250902-rk3588-bgcolor-v1-1-fd97df91d89f@collabora.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250902-rk3588-bgcolor-v1-1-fd97df91d89f@collabora.com> X-Patchwork-Hint: comment On Tue, Sep 02, 2025 at 12:27:56PM +0300, Cristian Ciocaltea wrote: > Some display controllers can be hardware programmed to show non-black > colors for pixels that are either not covered by any plane or are > exposed through transparent regions of higher planes. This feature can > help reduce memory bandwidth usage, e.g. in compositors managing a UI > with a solid background color while using smaller planes to render the > remaining content. > > To support this capability, introduce the BACKGROUND_COLOR standard DRM > mode property, which can be attached to a CRTC through the > drm_crtc_attach_background_color_property() helper function. > > Additionally, define a 64-bit ARGB format value to be built with the > help of a dedicated drm_argb64() utility macro. Individual color > components can be extracted with desired precision using the > corresponding DRM_ARGB64_*() macros. > > Co-developed-by: Matt Roper > Signed-off-by: Matt Roper > Signed-off-by: Cristian Ciocaltea > --- > drivers/gpu/drm/drm_atomic_state_helper.c | 1 + > drivers/gpu/drm/drm_atomic_uapi.c | 4 ++++ > drivers/gpu/drm/drm_blend.c | 37 +++++++++++++++++++++++++++---- > drivers/gpu/drm/drm_mode_config.c | 6 +++++ > include/drm/drm_blend.h | 4 +++- > include/drm/drm_crtc.h | 12 ++++++++++ > include/drm/drm_mode_config.h | 5 +++++ > include/uapi/drm/drm_mode.h | 30 +++++++++++++++++++++++++ > 8 files changed, 94 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c > index 7142e163e618ea0d7d9d828e1bd9ff2a6ec0dfeb..359264cf467c5270b77f0b04548073bc92cb812e 100644 > --- a/drivers/gpu/drm/drm_atomic_state_helper.c > +++ b/drivers/gpu/drm/drm_atomic_state_helper.c > @@ -75,6 +75,7 @@ __drm_atomic_helper_crtc_state_reset(struct drm_crtc_state *crtc_state, > struct drm_crtc *crtc) > { > crtc_state->crtc = crtc; > + crtc_state->background_color = drm_argb64(0xffff, 0, 0, 0); > } > EXPORT_SYMBOL(__drm_atomic_helper_crtc_state_reset); > > diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c > index 85dbdaa4a2e25878c953b9b41539c8566d55c6d9..a447cb119aaa6cd11348be77b39f342a1386836d 100644 > --- a/drivers/gpu/drm/drm_atomic_uapi.c > +++ b/drivers/gpu/drm/drm_atomic_uapi.c > @@ -407,6 +407,8 @@ static int drm_atomic_crtc_set_property(struct drm_crtc *crtc, > &replaced); > state->color_mgmt_changed |= replaced; > return ret; > + } else if (property == config->background_color_property) { > + state->background_color = val; > } else if (property == config->prop_out_fence_ptr) { > s32 __user *fence_ptr = u64_to_user_ptr(val); > > @@ -452,6 +454,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc, > *val = (state->ctm) ? state->ctm->base.id : 0; > else if (property == config->gamma_lut_property) > *val = (state->gamma_lut) ? state->gamma_lut->base.id : 0; > + else if (property == config->background_color_property) > + *val = state->background_color; > else if (property == config->prop_out_fence_ptr) > *val = 0; > else if (property == crtc->scaling_filter_property) > diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c > index 6852d73c931ce32e62062e2b8f8c5e38612d5210..5a287d12685b007a2732f510f62675f500e53727 100644 > --- a/drivers/gpu/drm/drm_blend.c > +++ b/drivers/gpu/drm/drm_blend.c > @@ -191,10 +191,6 @@ > * plane does not expose the "alpha" property, then this is > * assumed to be 1.0 > * > - * 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). > - * > * SCALING_FILTER: > * Indicates scaling filter to be used for plane scaler > * > @@ -207,6 +203,23 @@ > * > * Drivers can set up this property for a plane by calling > * drm_plane_create_scaling_filter_property > + * > + * The property extensions described above all apply to the plane. Drivers > + * may also expose the following crtc property extension: > + * > + * BACKGROUND_COLOR: > + * Background color is set via drm_crtc_attach_background_color_property(). > + * It controls the ARGB color of a full-screen layer that exists below all > + * planes. This color will be used for pixels not covered by any plane and > + * may also be blended with plane contents as allowed by a plane's alpha > + * values. The background color defaults to black, and is assumed to be > + * black for drivers that do not expose this property. Although background > + * color isn't a plane, it is assumed that the color provided here > + * undergoes the same pipe-level degamma/CSC/gamma transformations that > + * planes undergo. Note that the color value provided here includes an > + * alpha channel, hence non-opaque background color values are allowed, but > + * are generally only honored in special cases (e.g. when a memory > + * writeback connector is in use). > */ > > /** > @@ -621,3 +634,19 @@ int drm_plane_create_blend_mode_property(struct drm_plane *plane, > return 0; > } > EXPORT_SYMBOL(drm_plane_create_blend_mode_property); > + > +/** > + * drm_crtc_attach_background_color_property - attach background color property > + * @crtc: drm crtc > + * > + * Attaches the background color property to @crtc. The property defaults to > + * solid black and will accept 64-bit ARGB values in the format generated by > + * drm_argb64(). > + */ > +void drm_crtc_attach_background_color_property(struct drm_crtc *crtc) > +{ > + drm_object_attach_property(&crtc->base, > + crtc->dev->mode_config.background_color_property, > + drm_argb64(0xffff, 0, 0, 0)); > +} > +EXPORT_SYMBOL(drm_crtc_attach_background_color_property); > diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c > index 25f376869b3a41d47bbe72b0df3e35cad142f3e6..6d70bfab45ca2bb81ed3ca1940fd1cd85e8cc58e 100644 > --- a/drivers/gpu/drm/drm_mode_config.c > +++ b/drivers/gpu/drm/drm_mode_config.c > @@ -375,6 +375,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev) > return -ENOMEM; > dev->mode_config.gamma_lut_size_property = prop; > > + prop = drm_property_create_range(dev, 0, > + "BACKGROUND_COLOR", 0, U64_MAX); > + if (!prop) > + return -ENOMEM; > + dev->mode_config.background_color_property = prop; > + > prop = drm_property_create(dev, > DRM_MODE_PROP_IMMUTABLE | DRM_MODE_PROP_BLOB, > "IN_FORMATS", 0); > diff --git a/include/drm/drm_blend.h b/include/drm/drm_blend.h > index 88bdfec3bd8848acd1ef5742aaaa23483b332a2e..c7e888767c81c2745cd3cce88c10db4bbe305d1e 100644 > --- a/include/drm/drm_blend.h > +++ b/include/drm/drm_blend.h > @@ -31,8 +31,9 @@ > #define DRM_MODE_BLEND_COVERAGE 1 > #define DRM_MODE_BLEND_PIXEL_NONE 2 > > -struct drm_device; > struct drm_atomic_state; > +struct drm_crtc; > +struct drm_device; > struct drm_plane; > > static inline bool drm_rotation_90_or_270(unsigned int rotation) > @@ -58,4 +59,5 @@ int drm_atomic_normalize_zpos(struct drm_device *dev, > struct drm_atomic_state *state); > int drm_plane_create_blend_mode_property(struct drm_plane *plane, > unsigned int supported_modes); > +void drm_crtc_attach_background_color_property(struct drm_crtc *crtc); > #endif > diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h > index caa56e039da2a748cf40ebf45b37158acda439d9..4653dacc1077b9ed8fb4cf27cc84530ba1706f6a 100644 > --- a/include/drm/drm_crtc.h > +++ b/include/drm/drm_crtc.h > @@ -274,6 +274,18 @@ struct drm_crtc_state { > */ > struct drm_property_blob *gamma_lut; > > + /** > + * @background_color: > + * > + * RGB value representing the pipe's background color. The background > + * color (aka "canvas color") of a pipe is the color that will be used > + * for pixels not covered by a plane, or covered by transparent pixels > + * of a plane. The value here should be built using drm_argb64(), while > + * the individual color components can be extracted with desired > + * precision via the DRM_ARGB64_*() macros. > + */ > + u64 background_color; > + > /** > * @target_vblank: > * > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h > index 2e848b816218584eb077ed887bf97705f012a622..ea422afec5c4108a223dc872e1b6835ffc596cc3 100644 > --- a/include/drm/drm_mode_config.h > +++ b/include/drm/drm_mode_config.h > @@ -814,6 +814,11 @@ struct drm_mode_config { > * gamma LUT as supported by the driver (read-only). > */ > struct drm_property *gamma_lut_size_property; > + /** > + * @background_color_property: Optional CRTC property to set the > + * background color. > + */ > + struct drm_property *background_color_property; > > /** > * @suggested_x_property: Optional connector property with a hint for > diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h > index a122bea2559387576150236e3a88f99c24ad3138..4bd6a8ca8868109bcbe21f9f6e9864519c9d03ec 100644 > --- a/include/uapi/drm/drm_mode.h > +++ b/include/uapi/drm/drm_mode.h > @@ -1363,6 +1363,36 @@ struct drm_mode_closefb { > __u32 pad; > }; > > +/* > + * Put 16-bit ARGB values into a standard 64-bit representation that > + * can be used for ioctl parameters, inter-driver communication, etc. > + */ > +static inline __u64 > +drm_argb64(__u16 alpha, __u16 red, __u16 green, __u16 blue) > +{ > + return (__u64)alpha << 48 | (__u64)red << 32 | (__u64)green << 16 | blue; > +} > + > +/* > + * Extract the specified number of least-significant bits of a specific > + * color component from a standard 64-bit ARGB value. Why would you ever want the least significant bits? > + */ > +#define DRM_ARGB64_COMP(c, shift, numlsb) \ > + ((__u16)(((c) >> (shift)) & ((1UL << (numlsb) % 17) - 1))) > +#define DRM_ARGB64_ALPHA_LSB(c, numlsb) DRM_ARGB64_COMP(c, 48, numlsb) > +#define DRM_ARGB64_RED_LSB(c, numlsb) DRM_ARGB64_COMP(c, 32, numlsb) > +#define DRM_ARGB64_GREEN_LSB(c, numlsb) DRM_ARGB64_COMP(c, 16, numlsb) > +#define DRM_ARGB64_BLUE_LSB(c, numlsb) DRM_ARGB64_COMP(c, 0, numlsb) > + > +/* > + * Convenience wrappers to extract all 16 bits of a specific color > + * component from a standard 64-bit ARGB value. > + */ > +#define DRM_ARGB64_ALPHA(c) DRM_ARGB64_ALPHA_LSB(c, 16) > +#define DRM_ARGB64_RED(c) DRM_ARGB64_RED_LSB(c, 16) > +#define DRM_ARGB64_GREEN(c) DRM_ARGB64_GREEN_LSB(c, 16) > +#define DRM_ARGB64_BLUE(c) DRM_ARGB64_BLUE_LSB(c, 16) > + > #if defined(__cplusplus) > } > #endif > > -- > 2.51.0 -- Ville Syrjälä Intel