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Mon, 29 Dec 2025 14:52:43 +0000 Message-ID: <8338c85b-28c0-47f7-8e80-5448d7490f33@intel.com> Date: Mon, 29 Dec 2025 16:52:36 +0200 User-Agent: Mozilla Thunderbird Subject: Re: [Intel-wired-lan] [PATCH iwl-net v4] igc: fix race condition in TX timestamp read for register 0 To: Chwee-Lin Choong , Tony Nguyen , Przemek Kitszel , Andrew Lunn , "David S . 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This ensures any timestamp captured > during the race window will be detected. > > Old sequence: > 1. Check TXTT_0 ready bit > 2. Read TXSTMPL_0 (baseline) > 3. Read TXSTMPH_0 (interrupt workaround) > 4. Read TXSTMPL_0 (detect changes vs baseline) > > New sequence: > 1. Read TXSTMPL_0 (baseline) > 2. Check TXTT_0 ready bit > 3. Read TXSTMPH_0 (interrupt workaround) > 4. Read TXSTMPL_0 (detect changes vs baseline) > > Fixes: c789ad7cbebc ("igc: Work around HW bug causing missing timestamps") > Suggested-by: Avi Shalev > Reviewed-by: Aleksandr Loktionov > Co-developed-by: Song Yoong Siang > Signed-off-by: Song Yoong Siang > Signed-off-by: Chwee-Lin Choong > --- > v1: https://patchwork.ozlabs.org/project/intel-wired-lan/patch/20250918183811.31270-1-chwee.lin.choong@intel.com/ > v2: https://patchwork.ozlabs.org/project/intel-wired-lan/patch/20251127134927.2133-1-chwee.lin.choong@intel.com/ > v3: https://patchwork.ozlabs.org/project/intel-wired-lan/patch/20251127151137.2883-1-chwee.lin.choong@intel.com/ > > changelog: > v1 -> v2 > - Added detailed comments explaining the hardware bug workaround and race > detection mechanism > v2 -> v3 > - Removed extra export file added by mistake > v3 -> v4 > - Added co-developer > --- > drivers/net/ethernet/intel/igc/igc_ptp.c | 43 ++++++++++++++---------- > 1 file changed, 25 insertions(+), 18 deletions(-) > Tested-by: Avigail Dahan