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 E83B7D75E54 for ; Fri, 22 Nov 2024 14:06:47 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0801610EBA9; Fri, 22 Nov 2024 14:06:46 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="CSa3LyLy"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.16]) by gabe.freedesktop.org (Postfix) with ESMTPS id 67E2F10EBA4; Fri, 22 Nov 2024 14:06:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1732284405; x=1763820405; h=date:from:to:cc:subject:message-id:reply-to:references: mime-version:in-reply-to; bh=Mh2fcL/PqSSF44NqD5j7AIgjDasJ295whoWJkqgrAsE=; b=CSa3LyLyZdaIBJ0rQzMDnfGZgAHEE06QxCEiIKbUbi9KuenzrmrhaODw wLPhtLX8Ybjpqq8aNtaoeaekh5zeFjK81yYkPmHyjxdmYtqIUBzL7ueEC XU4hl2khKtSInaSULzxvvw9ODoZeu/4AJYhWYRYYaGDUnx45WjVROhY5T LH6/GTt9efVr4I/+uXMQCuK/fptFeH38t/pysylcyKqB5KMunPFQ2I/ad WlgzdLZoqc+Ec61qGx4sodtv0ldZLj/uA1uUWt7vqbbyci0WcvT3Hk55y h1z6tGdyoovz78v04yJYtdDf1MlB92AxjZbTPzfyxS8Pin0WxDXvrFrhZ w==; X-CSE-ConnectionGUID: d9j7ky9gSbeh3iIMfpHQJg== X-CSE-MsgGUID: QAI1WGcPTxqraeqj35vAbA== X-IronPort-AV: E=McAfee;i="6700,10204,11264"; a="32597329" X-IronPort-AV: E=Sophos;i="6.12,175,1728975600"; d="scan'208";a="32597329" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa108.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Nov 2024 06:06:41 -0800 X-CSE-ConnectionGUID: tCloOKjXS3iCZqGUKaC/zA== X-CSE-MsgGUID: z9A7m2W6QZmRjD5oDf0tMw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,175,1728975600"; d="scan'208";a="95374755" Received: from ideak-desk.fi.intel.com ([10.237.72.78]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Nov 2024 06:06:38 -0800 Date: Fri, 22 Nov 2024 16:07:13 +0200 From: Imre Deak To: Jani Nikula Cc: Lyude Paul , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org Subject: Re: [PATCH 1/3] drm/dp: extract drm_dp_dpcd_poll_act_handled() Message-ID: References: <3d91f7b6639960fe688eb6ae0236254adae3e82d.1731942780.git.jani.nikula@intel.com> <87bjy7zcdn.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87bjy7zcdn.fsf@intel.com> 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 Fri, Nov 22, 2024 at 02:22:44PM +0200, Jani Nikula wrote: > On Wed, 20 Nov 2024, Imre Deak wrote: > > On Mon, Nov 18, 2024 at 05:14:52PM +0200, Jani Nikula wrote: > >> SST with 128b/132b channel coding needs this too. Extract to a separate > >> helper, independent of MST. > >> > >> Pass timeout in as a parameter, anticipating that we can reduce the > >> timeout for SST. > > > > I wish there was a DP Standard section making the above clear, > > but I suppose we just deduct that except of the side-band messaging, > > every other payload programming and ACT signaling is required for > > 128b/132b SST. The closest I found explaing the above is 5.7.5. Allocation Change Trigger in DP Standard v2.1, maybe worth mentioning it in the commit log. > Ping. Okay to merge, or do we want to mull over the the timeout? My R-b still applies, if that's enough for merging. > I'm primarily trying to do a non-functional change. I could omit the > timeout parameter, but for non-hubs three seconds seems excessive, and > reducing it for hubs too is a can of worms I prefer keeping the lid on > top. > > > Cc: Lyude Paul > > > >> Signed-off-by: Jani Nikula > >> --- > >> drivers/gpu/drm/display/drm_dp_helper.c | 54 ++++++++++++++++++- > >> drivers/gpu/drm/display/drm_dp_mst_topology.c | 36 +------------ > >> include/drm/display/drm_dp_helper.h | 2 + > >> 3 files changed, 57 insertions(+), 35 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c > >> index 6ee51003de3c..b7e03bf02cd8 100644 > >> --- a/drivers/gpu/drm/display/drm_dp_helper.c > >> +++ b/drivers/gpu/drm/display/drm_dp_helper.c > >> @@ -22,15 +22,16 @@ > >> > >> #include > >> #include > >> +#include > >> #include > >> #include > >> #include > >> +#include > >> #include > >> #include > >> #include > >> #include > >> #include > >> -#include > >> > >> #include > >> #include > >> @@ -779,6 +780,57 @@ int drm_dp_dpcd_read_phy_link_status(struct drm_dp_aux *aux, > >> } > >> EXPORT_SYMBOL(drm_dp_dpcd_read_phy_link_status); > >> > >> +static int read_payload_update_status(struct drm_dp_aux *aux) > >> +{ > >> + int ret; > >> + u8 status; > >> + > >> + ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status); > >> + if (ret < 0) > >> + return ret; > >> + > >> + return status; > >> +} > >> + > >> +/** > >> + * drm_dp_dpcd_poll_act_handled() - Polls for ACT handled status. > >> + * @aux: DisplayPort AUX channel > >> + * @timeout_ms: Timeout in ms > >> + * > >> + * Tries waiting for the sink to finish updating its payload table by polling > >> + * for the ACT handled bit for up to @timeout_ms milliseconds, defaulting to > >> + * 3000 ms if 0. > >> + * > >> + * Returns: > >> + * 0 if the ACT was handled in time, negative error code on failure. > >> + */ > >> +int drm_dp_dpcd_poll_act_handled(struct drm_dp_aux *aux, int timeout_ms) > > > > I wonder if it'd make sense to namespace these helpers using ll_mtp or mtp. > > Honestly I think there's already enough of an acronym jumble in the > name. At least "drm_dp_dpcd" is common for most functions around here. > > > BR, > Jani. > > > > >> +{ > >> + int ret, status; > >> + > > > > Extra w/s. > > > > Regardless of the namespace comment: > > > > Reviewed-by: Imre Deak > > > >> + /* default to 3 seconds, this is arbitrary */ > >> + timeout_ms = timeout_ms ?: 3000; > >> + > >> + ret = readx_poll_timeout(read_payload_update_status, aux, status, > >> + status & DP_PAYLOAD_ACT_HANDLED || status < 0, > >> + 200, timeout_ms * USEC_PER_MSEC); > >> + if (ret < 0 && status >= 0) { > >> + drm_err(aux->drm_dev, "Failed to get ACT after %d ms, last status: %02x\n", > >> + timeout_ms, status); > >> + return -EINVAL; > >> + } else if (status < 0) { > >> + /* > >> + * Failure here isn't unexpected - the hub may have > >> + * just been unplugged > >> + */ > >> + drm_dbg_kms(aux->drm_dev, "Failed to read payload table status: %d\n", status); > >> + return status; > >> + } > >> + > >> + return 0; > >> +} > >> +EXPORT_SYMBOL(drm_dp_dpcd_poll_act_handled); > >> + > >> static bool is_edid_digital_input_dp(const struct drm_edid *drm_edid) > >> { > >> /* FIXME: get rid of drm_edid_raw() */ > >> diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c > >> index ac90118b9e7a..2bdbc1eb282b 100644 > >> --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c > >> +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c > >> @@ -29,7 +29,6 @@ > >> #include > >> #include > >> #include > >> -#include > >> > >> #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS) > >> #include > >> @@ -4723,18 +4722,6 @@ static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr, > >> return ret; > >> } > >> > >> -static int do_get_act_status(struct drm_dp_aux *aux) > >> -{ > >> - int ret; > >> - u8 status; > >> - > >> - ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status); > >> - if (ret < 0) > >> - return ret; > >> - > >> - return status; > >> -} > >> - > >> /** > >> * drm_dp_check_act_status() - Polls for ACT handled status. > >> * @mgr: manager to use > >> @@ -4752,28 +4739,9 @@ int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr) > >> * There doesn't seem to be any recommended retry count or timeout in > >> * the MST specification. Since some hubs have been observed to take > >> * over 1 second to update their payload allocations under certain > >> - * conditions, we use a rather large timeout value. > >> + * conditions, we use a rather large timeout value of 3 seconds. > >> */ > >> - const int timeout_ms = 3000; > >> - int ret, status; > >> - > >> - ret = readx_poll_timeout(do_get_act_status, mgr->aux, status, > >> - status & DP_PAYLOAD_ACT_HANDLED || status < 0, > >> - 200, timeout_ms * USEC_PER_MSEC); > >> - if (ret < 0 && status >= 0) { > >> - drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n", > >> - timeout_ms, status); > >> - return -EINVAL; > >> - } else if (status < 0) { > >> - /* > >> - * Failure here isn't unexpected - the hub may have > >> - * just been unplugged > >> - */ > >> - drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status); > >> - return status; > >> - } > >> - > >> - return 0; > >> + return drm_dp_dpcd_poll_act_handled(mgr->aux, 3000); > >> } > >> EXPORT_SYMBOL(drm_dp_check_act_status); > >> > >> diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h > >> index 279624833ea9..38eea21d1082 100644 > >> --- a/include/drm/display/drm_dp_helper.h > >> +++ b/include/drm/display/drm_dp_helper.h > >> @@ -567,6 +567,8 @@ int drm_dp_dpcd_read_phy_link_status(struct drm_dp_aux *aux, > >> enum drm_dp_phy dp_phy, > >> u8 link_status[DP_LINK_STATUS_SIZE]); > >> > >> +int drm_dp_dpcd_poll_act_handled(struct drm_dp_aux *aux, int timeout_ms); > >> + > >> bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux, > >> u8 real_edid_checksum); > >> > >> -- > >> 2.39.5 > >> > > -- > Jani Nikula, Intel