From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.15]) (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 6FB1B15B149 for ; Mon, 19 Aug 2024 08:45:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724057146; cv=none; b=CFWujjPCNC0zO58tLNe0Z1h04mY1WDmICdyb8G/2XFUHOjYAXsuNrOXUg4bCZljFGPlEIEDMMNwrcXAZ1eYgFPsONG+cwhkcNvCOY0skPdjslKy9mzFYye3GxadxjlVAqR2NPIVKHe5S0krGkUMFP7pyyj1TZ2LZMXiI/aOnasI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724057146; c=relaxed/simple; bh=BwO9G9DSxzsNbJAx83jRWAZlxWASmFoV86cMBGMNnX8=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=GplFfx8mg1JHhN8Rt8aXVhT7RYJC5wDZzJVq8odU4d3/yNTnBi3l3I0hWFwsIu0abQSBRoUdHsVySW13DgE2NP/38+vMyNiQhW1jq6mjhHUw3OdHeewPkqjMAMWrWFiy4SgrL8y2vgF6pLOW2TxkLlH9ZnJgZWwuze8H1RjudaM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=ADrQA+xJ; arc=none smtp.client-ip=192.198.163.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="ADrQA+xJ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1724057145; x=1755593145; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version:content-transfer-encoding; bh=BwO9G9DSxzsNbJAx83jRWAZlxWASmFoV86cMBGMNnX8=; b=ADrQA+xJcDdptM/WgSWkFM60z4YCNnXPZCndAi1pILND+l4TXAdfQIJ9 Yrob4YlDOmNxeySq1c9ldX+ADx8IejECWxVqEtLzdrFjVGJ+t3VQWMopD u3d+Yc1+3MU0yzd+E2a+5pwkECs1Vpnx7hr0bLVDjVR2/8RTs4fQl95HA x96wWD6heXdb2FsgnGkVuRF0z34nA2JdLmcDmuOSxfSCqSCdeh4LQRZtr o7uIUss9qmSLrfSTZbRAKYTCYXQKz0C1QDKHT5E0pnSOuAuz3iWkHG3TY PzPFyBmzAYA4glPSn7b8NBLSTDFtXEcl9pkkmqdY23dTSEvNUe/GvPzPF Q==; X-CSE-ConnectionGUID: oB7QIaQ0SMOgoC7tkeaLEA== X-CSE-MsgGUID: Ozz40xm0QO+9JWeYIWQwJw== X-IronPort-AV: E=McAfee;i="6700,10204,11168"; a="22451304" X-IronPort-AV: E=Sophos;i="6.10,158,1719903600"; d="scan'208";a="22451304" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Aug 2024 01:45:44 -0700 X-CSE-ConnectionGUID: K2j25Us7SbStyTFdemgwLg== X-CSE-MsgGUID: iw+RIGyQTc+pBwxsD/u7rA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,158,1719903600"; d="scan'208";a="60358532" Received: from mwiniars-desk2.ger.corp.intel.com (HELO localhost) ([10.245.246.70]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Aug 2024 01:45:37 -0700 From: Jani Nikula To: Thomas =?utf-8?Q?Wei=C3=9Fschuh?= , Harry Wentland , Leo Li , Rodrigo Siqueira , Alex Deucher , Christian =?utf-8?Q?K=C3=B6nig?= , Xinhui Pan , David Airlie , Daniel Vetter , jinzh , Aric Cyr , Alan Liu , Tony Cheng , Andrey Grodzovsky , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann Cc: amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Harry Wentland , Thomas =?utf-8?Q?Wei=C3=9Fschuh?= Subject: Re: [PATCH 10/12] drm/edid: add a helper to compare two EDIDs In-Reply-To: <20240818-amdgpu-drm_edid-v1-10-aea66c1f7cf4@weissschuh.net> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20240818-amdgpu-drm_edid-v1-0-aea66c1f7cf4@weissschuh.net> <20240818-amdgpu-drm_edid-v1-10-aea66c1f7cf4@weissschuh.net> Date: Mon, 19 Aug 2024 11:45:34 +0300 Message-ID: <871q2k7vf5.fsf@intel.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=utf-8 Content-Transfer-Encoding: quoted-printable On Sun, 18 Aug 2024, Thomas Wei=C3=9Fschuh wrote: > As struct drm_edid is opaque, drivers can't directly memcmp() the > contained data. Add a helper to provide this functionality. I'm not sure why drivers would need to compare EDIDs. The only user was added in commit eb815442e840 ("drm/amd/display: don't create new dc_sink if nothing changed at detection") with absolutely no explanation why. Other drivers use connector->epoch_counter to see if the EDID or status changed. BR, Jani. > > Signed-off-by: Thomas Wei=C3=9Fschuh > --- > drivers/gpu/drm/drm_edid.c | 18 ++++++++++++++++++ > include/drm/drm_edid.h | 1 + > 2 files changed, 19 insertions(+) > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > index 69fb11741abd..c2493c983a64 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -1840,6 +1840,24 @@ static bool drm_edid_eq(const struct drm_edid *drm= _edid, > return true; > } >=20=20 > +/** > + * drm_edid_equal - compare two EDID > + * @drm_edid_a: First EDID data > + * @drm_edid_b: Second EDID data > + * > + * Compare two EDIDs for equality (including extensions) > + * > + * Return: True if the EDIDs are equal, false otherwise. > + */ > +bool drm_edid_equal(const struct drm_edid *drm_edid_a, const struct drm_= edid *drm_edid_b) > +{ > + if (!drm_edid_b) > + return !drm_edid_a; > + > + return drm_edid_eq(drm_edid_a, drm_edid_b->edid, drm_edid_b->size); > +} > +EXPORT_SYMBOL(drm_edid_equal); > + > enum edid_block_status { > EDID_BLOCK_OK =3D 0, > EDID_BLOCK_READ_FAIL, > diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h > index a5b377c4a342..35b40a9d3350 100644 > --- a/include/drm/drm_edid.h > +++ b/include/drm/drm_edid.h > @@ -456,6 +456,7 @@ drm_display_mode_from_cea_vic(struct drm_device *dev, > const struct drm_edid *drm_edid_alloc(const void *edid, size_t size); > const struct drm_edid *drm_edid_dup(const struct drm_edid *drm_edid); > void drm_edid_free(const struct drm_edid *drm_edid); > +bool drm_edid_equal(const struct drm_edid *drm_edid_a, const struct drm_= edid *drm_edid_b); > bool drm_edid_valid(const struct drm_edid *drm_edid); > const struct edid *drm_edid_raw(const struct drm_edid *drm_edid); > const struct drm_edid *drm_edid_read(struct drm_connector *connector); --=20 Jani Nikula, Intel