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Message-ID: <c1514314-cfdf-65d1-986f-de360b4ee719@linux.intel.com>
Date:   Wed, 5 Jul 2023 14:06:37 +0300
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Subject: Re: [Intel-wired-lan] [PATCH net v2 5/6] igc: Fix launchtime before
 start of cycle
To:     Florian Kauer <florian.kauer@linutronix.de>,
        Jesse Brandeburg <jesse.brandeburg@intel.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>,
        Vinicius Costa Gomes <vinicius.gomes@intel.com>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Tan Tee Min <tee.min.tan@linux.intel.com>,
        Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>,
        Aravindhan Gunasekaran <aravindhan.gunasekaran@intel.com>,
        Malli C <mallikarjuna.chilakala@intel.com>
Cc:     netdev@vger.kernel.org, kurt@linutronix.de,
        intel-wired-lan@lists.osuosl.org, linux-kernel@vger.kernel.org
References: <20230619100858.116286-1-florian.kauer@linutronix.de>
 <20230619100858.116286-6-florian.kauer@linutronix.de>
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From:   "naamax.meir" <naamax.meir@linux.intel.com>
In-Reply-To: <20230619100858.116286-6-florian.kauer@linutronix.de>
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On 6/19/2023 13:08, Florian Kauer wrote:
> It is possible (verified on a running system) that frames are processed
> by igc_tx_launchtime with a txtime before the start of the cycle
> (baset_est).
> 
> However, the result of txtime - baset_est is written into a u32,
> leading to a wrap around to a positive number. The following
> launchtime > 0 check will only branch to executing launchtime = 0
> if launchtime is already 0.
> 
> Fix it by using a s32 before checking launchtime > 0.
> 
> Fixes: db0b124f02ba ("igc: Enhance Qbv scheduling by using first flag bit")
> Signed-off-by: Florian Kauer <florian.kauer@linutronix.de>
> Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
> ---
>   drivers/net/ethernet/intel/igc/igc_main.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)


Tested-by: Naama Meir <naamax.meir@linux.intel.com>