From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender5-op-o11.zoho.com (sender5-op-o11.zoho.com [165.173.182.11]) (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 F28C753A8AC for ; Tue, 8 Sep 2026 22:19:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=165.173.182.11 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788905947; cv=pass; b=BsLVbiRky54K6lD6i4ousbEoRA0xJua2juVVP4Ft+SN+W4/ESBky/DrpwWh8m+nznk/n/8e+p9RZnVEnJZ9NHldavywvmK9Zo2laYewatVirmvDX6hvAazVYiVaCQ4BlGFhUNYIn0LrrWlSj5W5JlBnwUFs7GQm5DSJcAMLs+Tk= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788905947; c=relaxed/simple; bh=snOQHJlJlLtcKSy04YXjuNf7CJOjR/2uZnieHHCYJ40=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=bT4/WUwlG3EgMNJ7FPoldZEwAUs4T18yZgqsX4pivA9VucVi0p5YlMdnoB5QR/wiTuQkZCGGhwtOTBMQHivbBacnX20+cKgYCi/5MdPnCpLTzHVQe820i8uxIPC7FHs+QyhV+gqALVjUEod9dNHN7HO2OTrFQxbKgMn1lSoCTiw= 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=leandro.ribeiro@collabora.com header.b=kTEnG4Aw; arc=pass smtp.client-ip=165.173.182.11 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=leandro.ribeiro@collabora.com header.b="kTEnG4Aw" ARC-Seal: i=1; a=rsa-sha256; t=1788905916; cv=none; d=zohomail.com; s=zohoarc; b=ZfQ1fHSTdL4Utckb7F8TIEPF3XaBGg+HB/ABRvZ2oKPwNVS7UXmtC0YbskMcdJirF9B8Nuf9HJJUL/52hC6kXWK13Cs+x1Vv0YdltRMce2SzXd51z5Uq+wH8SJSqAMWoj2/oCUiWj/HD/WXqAYm9jMKJWj5WjrGWez755kqyJ+Q= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1788905916; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:Subject:Subject:To:To:Message-Id:Reply-To; bh=uX34t09K/6FyPyum4/uGWqSmdiYpZyqWkAPNdfi7dkI=; b=hQEcRL0GUdUoRow6VydCozYW+dfP+j7hNI4HQ3jgRSrUps2d9+wn1Yx8IvXlTlR43XRiYotFBeoioGtz8fOlXpGMpc+bZogqOmZhzL3yxbool4PWEvLY6XZMer7X6mvWEUtHl2Sw+XDrztYuZr9B3Ck0Vwdnt6sTi+/Z4MWgSAc= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=leandro.ribeiro@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1788905916; s=zohomail; d=collabora.com; i=leandro.ribeiro@collabora.com; h=Message-ID:Date:Date:MIME-Version:Subject:Subject:To:To:Cc:Cc:From:From:In-Reply-To:Content-Type:Content-Transfer-Encoding:Message-Id:Reply-To; bh=uX34t09K/6FyPyum4/uGWqSmdiYpZyqWkAPNdfi7dkI=; b=kTEnG4AweUAcrf2bnxFvoVfIEu29rIm3OKOqdng6yADsoBA11ONtYq2fQ+Jo7eJA IXhyzrzo50W1FKYnK94G8Q7c7Q0q8oFM2Yusis8f4DFxf+smZxAWSKSPdMj28uFK1dM qkLJYDxWoydnHqqDSAkShJmIA2KLkaHIuKcIvzM0= Received: by mx.zohomail.com with SMTPS id 1788905915266449.26774191890786; Tue, 8 Sep 2026 15:18:35 -0700 (PDT) Message-ID: <44c5ceae-4824-4b45-878c-1aac9e646116@collabora.com> Date: Tue, 8 Sep 2026 19:18:29 -0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] drm/vkms: Add pixel blend mode property To: oushixiong1025@163.com, Louis Chauvet Cc: Haneen Mohammed , Simona Vetter , Melissa Wen , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Shixiong Ou , Ye Liu References: <20260828090257.788076-1-oushixiong1025@163.com> Content-Language: en-US From: Leandro Ribeiro In-Reply-To: <20260828090257.788076-1-oushixiong1025@163.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ZohoMailClient: External On 8/28/26 6:02 AM, oushixiong1025@163.com wrote: > From: Shixiong Ou > > The vkms planes expose formats with an alpha channel but do not > create the pixel blend mode property. Since > commit 860e748bddcc ("drm: ensure blend mode supported if pixel > format with alpha exposed") this triggers a warning during > drm_mode_config_validate(): > > [ 993.538979] ------------[ cut here ]------------ > [ 993.539000] [PLANE:35:plane-0] pixel format with alpha exposed but blend mode not setup > [ 993.539063] WARNING: drivers/gpu/drm/drm_mode_config.c:872 at drm_mode_config_validate > ...... > [ 993.539578] Call trace: > [ 993.539580] drm_mode_config_validate+0x398/0x558 [drm] (P) > [ 993.539707] drm_dev_register+0x1cc/0x2a0 [drm] > [ 993.539832] vkms_create+0x184/0x1d0 [vkms] > [ 993.539854] vkms_init+0x78/0xff8 [vkms] > ...... > > The vkms composer only blends premultiplied alpha, see > pre_mul_alpha_blend(), so create the property with > DRM_MODE_BLEND_PREMULTI as the only supported mode. > > Reported-by: Ye Liu > Signed-off-by: Shixiong Ou > --- > drivers/gpu/drm/vkms/vkms_plane.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c > index 6ee5c3f3207c..c4272f5f0354 100644 > --- a/drivers/gpu/drm/vkms/vkms_plane.c > +++ b/drivers/gpu/drm/vkms/vkms_plane.c > @@ -276,6 +276,7 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev, > { > struct drm_device *dev = &vkmsdev->drm; > struct vkms_plane *plane; > + int ret; > > plane = drmm_universal_plane_alloc(dev, struct vkms_plane, base, 0, > &vkms_plane_funcs, > @@ -287,6 +288,15 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev, > > drm_plane_helper_add(&plane->base, &vkms_plane_helper_funcs); > > + /* > + * The vkms composer only blends premultiplied alpha, see > + * pre_mul_alpha_blend(), so that is the only supported mode. > + */ > + ret = drm_plane_create_blend_mode_property(&plane->base, > + BIT(DRM_MODE_BLEND_PREMULTI)); > + if (ret) > + return ERR_PTR(ret); > + Hello, This looks good to me! But I think the comment in pre_mul_alpha_blend() could also be updated. It states: "The current DRM assumption is that pixel color values have been already pre-multiplied with the alpha channel values" Which is not true anymore. With this change: Reviewed-by: Leandro Ribeiro > drm_plane_create_rotation_property(&plane->base, DRM_MODE_ROTATE_0, > DRM_MODE_ROTATE_MASK | DRM_MODE_REFLECT_MASK); > -- Leandro Ribeiro