From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 F38B2227EAE; Tue, 29 Apr 2025 08:03:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745913826; cv=none; b=HqWiXiRKbxaPln8VDHWIG8AFzdd1HGeSg7VDTdzqUtRJfYlTCFOjz237+C+ogSE04Of2yaND8FsApChXPzu3gf1z0efYC/hU4iYO/RTjAeIIgj6ZLGUUrA2+pLe7YpGQWL+lDTlnXrYZtb6IOusQy2nOuf/dTxlVAa+1fr05Mzg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745913826; c=relaxed/simple; bh=pmshIlvLRAdRvDeLsdcl2kLYHfWtssSEGw+i8OfR21Q=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Hl2CZLE5GthVWZkOvGeunKGjJtYQ0pGG2r3QFF6fdhE9CFXRD5+whVcH1rJgevs2FNY8bOhg1mKyn4QeovBzcBBh2/uieEJvsxvVnyx9q0OEibCetg9WKO8HdecWnZhke/UN+DGI8WeZgUGRT2aAjaodMnH3BpH1tQEKJDyH/tA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Dz1MO+Di; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Dz1MO+Di" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 742C8C4CEE3; Tue, 29 Apr 2025 08:03:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745913825; bh=pmshIlvLRAdRvDeLsdcl2kLYHfWtssSEGw+i8OfR21Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Dz1MO+DiWtr9y2ztoIPuBon5YwwEoH0xVH+OZfkXRcZzqWoMYZ4YYU0O23F+k95Te 5y1UAv2PfUvdN1iouu6DcSUFlYD/1B5BuePdepcpHgZeGb9KwohRY7DRaardZOG4uA wPrQ0sTcoHvcF/vgHanR7SwrVhFVlRvfWrNvsG962NnmEAMNWv/crVv3vW8hB7URwM pVp3AAqDP/JVHWTO/p/oWxgUkhPP0WhJvQZdn+sjT1cBFpYbzQEyhyjZBEPHOcrUm4 jOjXOsYL75bu3DdLds793KongrHCe5RKYddb7LcQeQpPJACyaEmqShDKg7mwwVJ4CD A1PnVEBOxpIAQ== Received: from johan by xi.lan with local (Exim 4.97.1) (envelope-from ) id 1u9fwQ-000000007Pq-3tEE; Tue, 29 Apr 2025 10:03:47 +0200 Date: Tue, 29 Apr 2025 10:03:46 +0200 From: Johan Hovold To: Abel Vesa Cc: Aleksandrs Vinarskis , Dmitry Baryshkov , linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org, dmitry.baryshkov@oss.qualcomm.com, Rob Clark , Abhinav Kumar , Sean Paul , Marijn Suijten , David Airlie , Simona Vetter , laurentiu.tudor1@dell.com Subject: Re: drm/msm/dp: Introduce link training per-segment for LTTPRs Message-ID: References: <20250417021349.148911-1-alex.vinarskis@gmail.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=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Apr 29, 2025 at 10:50:55AM +0300, Abel Vesa wrote: > On 25-04-29 09:23:46, Johan Hovold wrote: > > On Mon, Apr 28, 2025 at 05:17:21PM +0300, Abel Vesa wrote: > > > On 25-04-28 14:47:04, Johan Hovold wrote: > > > > On Mon, Apr 28, 2025 at 11:06:39AM +0200, Aleksandrs Vinarskis wrote: > > > > > On Mon, 28 Apr 2025 at 09:45, Johan Hovold wrote: > > > > > > Does this mean that the incomplete LTTPR support in 6.15-rc1 broke > > > > > > adapters or docks with retimers in transparent mode? > > Ok, but my concern is if they may have worked in a default transparent > > mode. > > But if they are by default in transparent mode, doing the setup to > transparent mode will not break it in any way. It looks like it will, see below. > > > X13s doesn't have LTTPRs on-board so when reading the caps, LTTPRs count > > > would return 0 and none of the of the transparent/non-transparent setup > > > would happen. > > > > But this is the crux; does any off-board LTTPRs in transparent mode add > > to the count or not? If they don't, how would you ever learn that there > > are any LTTPRs? If they do, it seems we may have a problem here. > > Count gets increased either way. It doesn't matter if they are in > transparent mode or not. Thanks for confirming. So then it seems we do have a problem as since 6.15-rc1 drm_dp_lttpr_init() will switch all LTTPRs to non-transparent mode. Johan