From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (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 899833B389D; Mon, 13 Apr 2026 10:09:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776074969; cv=pass; b=rBvxQhSE+z0q9cQT6ERhbEyDavZ/k2roX3cvuQofABxSx7mndeHG4MpgCqaRLxdK5EIOWcVLBh7fEV+ohhXxDy5SFHGslV6faXLuEykhISmGL8Py/3fbfOxvKN3AcTyFceGTEM/MGIPQb+PUSJklAF7ebS0sGD9xS8euNYagO/g= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776074969; c=relaxed/simple; bh=c8N9bBN3IGkoX9tEk04qyx+hAcr9uJMIzrPuIxBa+Pk=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Z/8y1Qh2fLaT4gdr/Spi+bRAwHzZynb6fDh0dJyQincdkj+tyVV5wLEbqt12FZzKdJOUg2qgIEU52rQ3nelEnvYsojZxNob9xqnpBtdsHcgNB1lsuKZA3y5qty1bvHNsgd3PX/IO2DDY9D+p4d7lbnPMDPLIGAPFVaUguxPB6UQ= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b=ems3N+L1; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b="ems3N+L1" ARC-Seal: i=1; a=rsa-sha256; t=1776074925; cv=none; d=zohomail.com; s=zohoarc; b=CJb/whBAbd8gxkcHDvfgunaFUCaJOjg6DevgxYqaU3GOzCM5WLk5MXN3L91f1ORGYDOX8aw2fmMv7CGWhJYuGYt0lyREAa2HStE2d7vXSWBNwuz9IIYEGhF3AqPj+ZmveHSf0GO7KnBsQj9y12lQaaifr5IbzGeXKReIa8Bld3k= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1776074925; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=IH5low48GM+yv78IQ9owPpTrmwFuFjqqYcrTkdlKUr4=; b=nG+IuaXJaZh4EeeDVbpyfXXDC9A4SxcGAHxzoLswmIPqyYqhB2CcbMQbloGrRG5MxvS9KTZSjlCXXD1e2aT5zCOQ++RevNvgGQ1Uj8rA2T6BQYXuJqs9uT1EvlyoG2L8Ug6KAqdkdHDZeqnPQVjQcFmHvQ61/llLZvP99kuc1C4= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=nicolas.frattaroli@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1776074925; s=zohomail; d=collabora.com; i=nicolas.frattaroli@collabora.com; h=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:References:In-Reply-To:To:To:Cc:Cc:Reply-To; bh=IH5low48GM+yv78IQ9owPpTrmwFuFjqqYcrTkdlKUr4=; b=ems3N+L1L6VqnJmubJ47l3htgrQRrQP8rFHznCNikhd08TGBL4NQ4OWhbuhl01BK haki4gk5S7BtV9dUqsqVSIQ/hgHxIx9QDq7r2fvThcp1iCpwZL9JhjpL8zv/btLM1ou vUdFbTmVOI4LenihaqxBJn/91qKRVX5tQ4io254Y= Received: by mx.zohomail.com with SMTPS id 1776074922983125.99840353906723; Mon, 13 Apr 2026 03:08:42 -0700 (PDT) From: Nicolas Frattaroli Date: Mon, 13 Apr 2026 12:07:21 +0200 Subject: [PATCH v13 07/27] drm/atomic-helper: Add HDMI bridge output bus formats helper Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260413-color-format-v13-7-ab37d4dfba48@collabora.com> References: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com> In-Reply-To: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com> To: Harry Wentland , Leo Li , Rodrigo Siqueira , Alex Deucher , =?utf-8?q?Christian_K=C3=B6nig?= , David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Sandy Huang , =?utf-8?q?Heiko_St=C3=BCbner?= , Andy Yan , Jani Nikula , Rodrigo Vivi , Joonas Lahtinen , Tvrtko Ursulin , Dmitry Baryshkov , Sascha Hauer , Rob Herring , Jonathan Corbet , Shuah Khan Cc: kernel@collabora.com, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, linux-doc@vger.kernel.org, Nicolas Frattaroli X-Mailer: b4 0.15.2 The drm_bridge_funcs atomic_get_output_bus_fmts operation should be the same for likely every HDMI connector bridge, unless such an HDMI connector bridge has some special hardware restrictions that I cannot envision yet. To avoid code duplication and standardize on a set of media bus formats that the HDMI output color formats translate to, add a common helper function that implements this operation to the drm bridge helpers. The function returns a list of output bus formats based on the HDMI bridge's current output bits-per-component, and its bitmask of supported color formats. To guard against future expansion of DRM_OUTPUT_COLOR_FORMAT outgrowing the hweight8 call, add a BUILD_BUG_ON statement where it's used that checks for DRM_OUTPUT_COLOR_FORMAT_COUNT. The justification for not using hweight32 in all cases is that not all ISAs have a popcount instruction, and will benefit from a smaller/faster software implementation that doesn't have to operate across all bits. The justification for not defining an hweight_color depending on the value of DRM_OUTPUT_COLOR_FORMAT_COUNT is that this count enum value is only known at compile time, not at preprocessor time. Signed-off-by: Nicolas Frattaroli --- drivers/gpu/drm/drm_atomic_helper.c | 81 +++++++++++++++++++++++++++++++++++++ include/drm/drm_atomic_helper.h | 7 ++++ 2 files changed, 88 insertions(+) diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 0de9748a82c6..9e62a24ab4b4 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include @@ -4095,3 +4096,83 @@ drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge, return input_fmts; } EXPORT_SYMBOL(drm_atomic_helper_bridge_propagate_bus_fmt); + +/** + * drm_atomic_helper_bridge_get_hdmi_output_bus_fmts - helper implementing + * atomic_get_output_bus_fmts for HDMI + * @bridge: pointer to &struct drm_bridge + * @bridge_state: pointer to the current bridge state + * @crtc_state: pointer to the current CRTC state + * @conn_state: pointer to the current connector state + * @num_output_fmts: pointer to where the number of entries in the returned array + * will be stored. Set to 0 if unsuccessful. + * + * Common implementation for the &drm_bridge_funcs.atomic_get_output_bus_fmts + * operation that's applicable to HDMI connectors. + * + * Returns: a newly allocated array of u32 values of length \*@num_output_fmts, + * representing all the MEDIA_BUS_FMTS\_ for the current connector state's + * chosen HDMI output bits per compoennt, or %NULL if it fails to allocate one. + */ +u32 * +drm_atomic_helper_bridge_get_hdmi_output_bus_fmts(struct drm_bridge *bridge, + struct drm_bridge_state *bridge_state, + struct drm_crtc_state *crtc_state, + struct drm_connector_state *conn_state, + unsigned int *num_output_fmts) +{ + unsigned int num_fmts = 0; + u32 *out_fmts; + + /* + * bridge->supported_formats is a bit field of BIT(enum drm_output_color_format) + * values. The smallest hweight that is smaller than or equal to + * %DRM_OUTPUT_COLOR_FORMAT_COUNT will do for counting set bits here. + */ + BUILD_BUG_ON(const_true(DRM_OUTPUT_COLOR_FORMAT_COUNT > 8)); + out_fmts = kmalloc_array(hweight8(bridge->supported_formats), + sizeof(u32), GFP_KERNEL); + if (!out_fmts) { + *num_output_fmts = 0; + return NULL; + } + + switch (conn_state->hdmi.output_bpc) { + case 12: + if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_RGB444)) + out_fmts[num_fmts++] = MEDIA_BUS_FMT_RGB121212_1X36; + if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444)) + out_fmts[num_fmts++] = MEDIA_BUS_FMT_YUV12_1X36; + if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422)) + out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYVY12_1X24; + if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR420)) + out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYYVYY12_0_5X36; + break; + case 10: + if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_RGB444)) + out_fmts[num_fmts++] = MEDIA_BUS_FMT_RGB101010_1X30; + if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444)) + out_fmts[num_fmts++] = MEDIA_BUS_FMT_YUV10_1X30; + if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422)) + out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYVY10_1X20; + if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR420)) + out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYYVYY10_0_5X30; + break; + default: + if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_RGB444)) + out_fmts[num_fmts++] = MEDIA_BUS_FMT_RGB888_1X24; + if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444)) + out_fmts[num_fmts++] = MEDIA_BUS_FMT_YUV8_1X24; + if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422)) + out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYVY8_1X16; + if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR420)) + out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYYVYY8_0_5X24; + break; + } + + *num_output_fmts = num_fmts; + + return out_fmts; +} +EXPORT_SYMBOL(drm_atomic_helper_bridge_get_hdmi_output_bus_fmts); + diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h index e154ee4f0696..7256eaca109b 100644 --- a/include/drm/drm_atomic_helper.h +++ b/include/drm/drm_atomic_helper.h @@ -295,4 +295,11 @@ drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge, u32 output_fmt, unsigned int *num_input_fmts); +u32 * +drm_atomic_helper_bridge_get_hdmi_output_bus_fmts(struct drm_bridge *bridge, + struct drm_bridge_state *bridge_state, + struct drm_crtc_state *crtc_state, + struct drm_connector_state *conn_state, + unsigned int *num_output_fmts); + #endif /* DRM_ATOMIC_HELPER_H_ */ -- 2.53.0