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 D8AF7C4828F for ; Wed, 7 Feb 2024 15:48:59 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2323D10E6EE; Wed, 7 Feb 2024 15:48:59 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="K4+V7s1k"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.18]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1CE4B10E6EE for ; Wed, 7 Feb 2024 15:48:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1707320937; x=1738856937; h=date:from:to:subject:message-id:reply-to:references: mime-version:content-transfer-encoding:in-reply-to; bh=PoD7wwo5SeSvVWp2uLvJqNhQQ4QGTQygaSh+VXQ0eto=; b=K4+V7s1kJPHPy4Dt71ecxZC5xzbZkN1nRQ17jNN75K4f/qWhrvF2FCRB TlFOhXpZ9WQeBo5s23Nq8vuJlP7hxC6/lUmBE6uoAi9Bg7EtKnAcnEaYM YNG4KEUZ7py5s3o5QygxP/eTJZo0BjPe9X/+ZR8F5wiUkgW5PwBmfZa7i UJKPpovDHRzTDHjiPQ+rSD2PvZF+fO3UtwboKVoV9wtFg8RoZsehZUQ0o 5rTyRSY/k9Cf0Fi85GYy1jrTuM/VMhgSXG0lJX2VigC/ExMpKKnxnue9A 9sZbkvDkxDTT6HRwZ/hWF2TfZVZk/aM/DhhKSbIskdOVUkwh1zuvCQwDm g==; X-IronPort-AV: E=McAfee;i="6600,9927,10977"; a="894860" X-IronPort-AV: E=Sophos;i="6.05,251,1701158400"; d="scan'208";a="894860" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Feb 2024 07:48:56 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.05,251,1701158400"; d="scan'208";a="32440784" Received: from unknown (HELO ideak-desk.fi.intel.com) ([10.237.66.155]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Feb 2024 07:48:55 -0800 Date: Wed, 7 Feb 2024 17:49:14 +0200 From: Imre Deak To: "Hogander, Jouni" , "intel-gfx@lists.freedesktop.org" Subject: Re: [PATCH 1/2] drm/i915: Prevent HW access during init from SDVO TV get_modes hook Message-ID: References: <20240206153910.1758057-1-imre.deak@intel.com> <20240206153910.1758057-2-imre.deak@intel.com> <47fac05618fb85725f9c0cfa694fb601c82b2a7f.camel@intel.com> <236599ca2b3982045a2515d4eaef16a2f23cefd5.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: imre.deak@intel.com Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Wed, Feb 07, 2024 at 04:10:28PM +0200, Imre Deak wrote: > On Wed, Feb 07, 2024 at 03:45:15PM +0200, Hogander, Jouni wrote: > > On Wed, 2024-02-07 at 15:26 +0200, Hogander, Jouni wrote: > > > On Tue, 2024-02-06 at 17:39 +0200, Imre Deak wrote: > > > > Prevent accessing the HW from the SDVO/TV get_modes connector hook. > > > > Returning 0 from the hook will make the caller - > > > > drm_helper_probe_single_connector_modes() - keep the previously > > > > detected > > > > mode list of the connector. > > > > > > > > I don't see where this is done? Not sure if looking at wrong place, > > > but I see it tries using some override edid and in case that fails > > > as well uses drm_add_modes_noedid? > > Some default and EDID override modes are also added to the connector > mode list, similarly to when the HW access in intel_sdvo_get_tv_modes() > fails (along with any modes specified via the kernel command line, which > happens unconditionally, see drm_helper_probe_add_cmdline_mode()). > > All the modes detected by the encoder detect and the connector get_modes > hooks gets added to the drm_connector::probed_modes list. From this > __drm_helper_update_and_validate() will copy any new modes to the > drm_connector::modes list (which will be returned to user space/kernel > client). Thus, returning 0 from the above TV connector get_modes hook > will preserve the list of modes on the drm_connector::modes list from an > earlier encoder detect/connector get_modes call. Drat, I realized the above is not quite correct. All the modes on drm_connector:modes will be flagged as MODE_STALE and removed by drm_mode_prune_invalid(). This means if get_modes() returns 0 only the default/override modes will be returned, not the ones detected in an earlier detect/get_modes call. I think this is ok, matching the case where HW access fails, but needs at least a clarficiation in the comment. Thanks for questioning it.. > > > > > > > > > > > > Signed-off-by: Imre Deak > > > > --- > > > > drivers/gpu/drm/i915/display/intel_sdvo.c | 4 ++++ > > > > 1 file changed, 4 insertions(+) > > > > > > > > diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c > > > > b/drivers/gpu/drm/i915/display/intel_sdvo.c > > > > index 2571ef5a1b211..ccea0efbd136f 100644 > > > > --- a/drivers/gpu/drm/i915/display/intel_sdvo.c > > > > +++ b/drivers/gpu/drm/i915/display/intel_sdvo.c > > > > @@ -2287,6 +2287,7 @@ static const struct drm_display_mode > > > > sdvo_tv_modes[] = { > > > > static int intel_sdvo_get_tv_modes(struct drm_connector > > > > *connector) > > > > > > I see intel_sdvo_get_tv_modes is called from intel_sdvo_get_modes. > > > Why > > > there is no need to do the same in intel_sdvo_get_lvds_modes and > > > intel_sdvo_get_ddc_modes as well? > > > > It seems you are taking care of intel_svdo_get_ddc_modes in next patch. > > Intel_svdo_get_lvds_modes doesn't touch the hw -> nothing to do there. > > > > > > > > BR, > > > > > > Jouni Högander > > > > > > > { > > > > struct intel_sdvo *intel_sdvo = > > > > intel_attached_sdvo(to_intel_connector(connector)); > > > > + struct drm_i915_private *i915 = to_i915(intel_sdvo- > > > > > base.base.dev); > > > > struct intel_sdvo_connector *intel_sdvo_connector = > > > > to_intel_sdvo_connector(connector); > > > > const struct drm_connector_state *conn_state = connector- > > > > > state; > > > > @@ -2298,6 +2299,9 @@ static int intel_sdvo_get_tv_modes(struct > > > > drm_connector *connector) > > > > DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", > > > > connector->base.id, connector->name); > > > > > > > > + if (!intel_display_driver_check_access(i915)) > > > > + return 0; > > > > + > > > > /* > > > > * Read the list of supported input resolutions for the > > > > selected TV > > > > * format. > > > > >