From mboxrd@z Thu Jan 1 00:00:00 1970 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 E70EDC5320E for ; Mon, 19 Aug 2024 08:45:45 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6C14110E212; Mon, 19 Aug 2024 08:45:45 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="IA6x6PZc"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.15]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1895310E20F; Mon, 19 Aug 2024 08:45:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1724057144; x=1755593144; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version:content-transfer-encoding; bh=BwO9G9DSxzsNbJAx83jRWAZlxWASmFoV86cMBGMNnX8=; b=IA6x6PZcX5xw0r8UaP6y7FnKIy7N/3NI3VQaNC9ni/Sb8pSf8UUKFrW0 5IK15gLvDwzwb+MJOFJsTtublpzlvcC2QQAyradZhPcqDPRqLJinqwdtz qhI0dFrQtmXoRAsSeqYfRvIvl91GFxxD4i8vgjWm2UAKi0GXrPZGibIvr BBZv47bWiupDHvbNAHDriGOZRcqCgxvRpJ7dmmRuEZurOqXSqlCgripCK hF0/DMaALu5tlX6NTIKdByueauVgC4VCGamWogEaCLfqBq6J/5tJUObjg Sy16vcBgl04q4NyPn78rJbZQ1h5drxSKUBPhEW+LaaT4hpyIrZURJu+VX g==; X-CSE-ConnectionGUID: yWmyTJYZT/mQx69Y9cBN5g== X-CSE-MsgGUID: tp0HeTQZTy6eQ73y6iOsRw== X-IronPort-AV: E=McAfee;i="6700,10204,11168"; a="22451312" X-IronPort-AV: E=Sophos;i="6.10,158,1719903600"; d="scan'208";a="22451312" 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> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" 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