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 B79231BDD9 for ; Sat, 4 Nov 2023 15:25:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="vFbreeA4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C433C433C7; Sat, 4 Nov 2023 15:25:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1699111537; bh=RXC0aVEzXpNQmrr7IVwVsn2Tuc9ENbNnCqjKZnXeNuU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=vFbreeA4celmK7CrhDLD7TDVutpD9Zl/06XOmuhANy00F0FjW+htciPxTCMz9PbTt C7ht5vYsiO+I5zEuFao7Cc1PDhw3sagdQAdSbFOUolNDVNiYl2+/rX+O0Q/QmRzsR8 s6VR94JRGX9eBaDNb1iI3yhK8iZATpW7S2BUS4pipVtB2zHvGnZOsOTJFI6Ntee0Rn OwPS2hbvSQpEGcvfiBWV0W6COmLAPqFf/Y4PC83rYFiqy4ICx99yfFMdL1bmdvoQhd 7ir2RMNGXTWeqpkDtGCPfn0fzEGCvueXn4Buco5G5HwoLVjIBWgENif4f8pRnWvaRI DDqLO3yUZoXxA== Date: Sat, 4 Nov 2023 11:25:23 -0400 From: Simon Horman To: Jacob Keller Cc: Anthony Nguyen , Intel Wired LAN , netdev@vger.kernel.org, Jesse Brandeburg Subject: Re: [PATCH iwl-net 3/3] ice: restore timestamp configuration after device reset Message-ID: <20231104152523.GI891380@kernel.org> References: <20231103234658.511859-1-jacob.e.keller@intel.com> <20231103234658.511859-4-jacob.e.keller@intel.com> Precedence: bulk X-Mailing-List: netdev@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: <20231103234658.511859-4-jacob.e.keller@intel.com> On Fri, Nov 03, 2023 at 04:46:58PM -0700, Jacob Keller wrote: > The driver calls ice_ptp_cfg_timestamp() during ice_ptp_prepare_for_reset() > to disable timestamping while the device is resetting. This operation > destroys the user requested configuration. While the driver does call > ice_ptp_cfg_timestamp in ice_rebuild() to restore some hardware settings > after a reset, it unconditionally passes true or false, resulting in > failure to restore previous user space configuration. > > This results in a device reset forcibly disabling timestamp configuration > regardless of current user settings. > > This was not detected previously due to a quirk of the LinuxPTP ptp4l > application. If ptp4l detects a missing timestamp, it enters a fault state > and performs recovery logic which includes executing SIOCSHWTSTAMP again, > restoring the now accidentally cleared configuration. > > Not every application does this, and for these applications, timestamps > will mysteriously stop after a PF reset, without being restored until an > application restart. > > Fix this by replacing ice_ptp_cfg_timestamp() with two new functions: > > 1) ice_ptp_disable_timestamp_mode() which unconditionally disables the > timestamping logic in ice_ptp_prepare_for_reset() and ice_ptp_release() > > 2) ice_ptp_restore_timestamp_mode() which calls > ice_ptp_restore_tx_interrupt() to restore Tx timestamping configuration, > calls ice_set_rx_tstamp() to restore Rx timestamping configuration, and > issues an immediate TSYN_TX interrupt to ensure that timestamps which > may have occurred during the device reset get processed. > > Modify the ice_ptp_set_timestamp_mode to directly save the user > configuration and then call ice_ptp_restore_timestamp_mode. This way, reset > no longer destroys the saved user configuration. > > This obsoletes the ice_set_tx_tstamp() function which can now be safely > removed. > > With this change, all devices should now restore Tx and Rx timestamping > functionality correctly after a PF reset without application intervention. > > Fixes: 77a781155a65 ("ice: enable receive hardware timestamping") > Fixes: ea9b847cda64 ("ice: enable transmit timestamps for E810 devices") > Signed-off-by: Jacob Keller > Reviewed-by: Jesse Brandeburg Reviewed-by: Simon Horman