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 BC132306B3E; Fri, 5 Sep 2025 14:55:53 +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=1757084153; cv=none; b=ole/Tw04teg6VbvsOPQcS7cjF30osNeJR7wT52jw7kMAzyQiD7gJqOnzpgWv3SnbeopJB+akiPiXqoYr9q1T6RfRdG2rJrbyb0BGfwk+pFepp2dkEEE0DwFMDSMQQeUMDd9StsEigGWjSoSW+Gs0dvVYn7/hshqlqhRoj7PkKG0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757084153; c=relaxed/simple; bh=I7ml6xJZ4Om5HnN19piLwI7G8H+aa9i/WG4hvv15vl8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mzpJjOx7Kxjnl9Q1W1rLViWtglxCyhqlgT93fD2dBWsXkBDOSR24qY0mhX0w4nVotsftvJ34prSIpYlgh3h6HTkLdtkKpz8ZQ3xDy0OPJ668xXTWA1B9ocwFAskUkDPEuNzhRqo+Lxxe7kl6SLjp8bM89AFpJqneBMlqW11fchg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=uwGf4Hg/; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="uwGf4Hg/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D6928C4CEF1; Fri, 5 Sep 2025 14:55:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1757084153; bh=I7ml6xJZ4Om5HnN19piLwI7G8H+aa9i/WG4hvv15vl8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uwGf4Hg/a1jC+V9Fs3rFsNph9GmL1uuDo/ajy9VYUeOmwlmDGYl2LiiHK3Wzjzh6+ lmT3Fa+injfqpAQSa37baIuL9Wrqo/XG/lixYWVwkswCj6Eld0NqyqUmP89A/j4faB cwstGDfkKtIcPLQnoanec9S5am+9eh3kMD1abD1k= Date: Fri, 5 Sep 2025 16:55:50 +0200 From: Greg Kroah-Hartman To: Imre Deak Cc: stable@vger.kernel.org, patches@lists.linux.dev, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Sasha Levin Subject: Re: [PATCH 6.16 139/142] Revert "drm/dp: Change AUX DPCD probe address from DPCD_REV to LANE0_1_STATUS" Message-ID: <2025090530-germicide-protozoan-8d0b@gregkh> References: <20250902131948.154194162@linuxfoundation.org> <20250902131953.603872091@linuxfoundation.org> <2025090551-setup-crescent-a670@gregkh> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Sep 05, 2025 at 04:45:34PM +0300, Imre Deak wrote: > On Fri, Sep 05, 2025 at 07:07:40AM +0200, Greg Kroah-Hartman wrote: > > On Fri, Sep 05, 2025 at 12:48:11AM +0300, Imre Deak wrote: > > > Hi Greg, > > > > > > On Tue, Sep 02, 2025 at 03:20:41PM +0200, Greg Kroah-Hartman wrote: > > > > 6.16-stable review patch. If anyone has any objections, please let me know. > > > > > > Thanks for queuing this and the corresponding reverts for the other > > > stable trees. This one patch doesn't match what I sent, the address > > > should be changed to DP_TRAINING_PATTERN_SET not to DP_DPCD_REV, see > > > [1]. I still think that's the correct thing to do here conforming to the > > > DP Standard and matching what the upstream kernel does, also solving a > > > link training issue for a DP2.0 docking station. > > > > > > The reverts queued for the other stable trees are correct, since for > > > now I do not want to change the behavior in those (i.e. those trees > > > should continue to use the DP_DPCD_REV register matching what's been the > > > case since the DPCD probing was introduced). > > > > Ick, why were the values different for different branches? That feels > > wrong, and is why I missed that. > > The requirement for changing the DPCD probe address was only > introduced/clarified by a recent DP Standard version (with the > introducation of LTTPR / UHBR link rates), so in the DRM code this got > changed only in v6.16.0. However, this change revealed a bug in the > firmwares of an eDP panel and Thunderbolt host, which also had to be > fixed/worked around. The only such remaining issue is the latter one > tracked at [1], which is now fixed by [2]. > > Based on all the above I still would like to keep the change only in the > v6.16 tree and not backport it to earlier stable trees, until having > more confidence that the change doesn't cause an issue for any sink > device. > > > Can you just send a fix-up patch for the one I got wrong? > > Ok, I can send a patch for v6.16.y on top of what is already queued > there. It's already in a release :) thanks, greg k-h