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Faizal Rahim 3fa593db45 igc: Fix packet still tx after gate close by reducing i226 MAC retry buffer
[ Upstream commit e037a26ead ]

Testing uncovered that even when the taprio gate is closed, some packets
still transmit.

According to i225/6 hardware errata [1], traffic might overflow the
planned QBV window. This happens because MAC maintains an internal buffer,
primarily for supporting half duplex retries. Therefore, even when the
gate closes, residual MAC data in the buffer may still transmit.

To mitigate this for i226, reduce the MAC's internal buffer from 192 bytes
to the recommended 88 bytes by modifying the RETX_CTL register value.

This follows guidelines from:
[1] Ethernet Controller I225/I22 Spec Update Rev 2.1 Errata Item 9:
    TSN: Packet Transmission Might Cross Qbv Window
[2] I225/6 SW User Manual Rev 1.2.4: Section 8.11.5 Retry Buffer Control

Note that the RETX_CTL register can't be used in TSN mode because half
duplex feature cannot coexist with TSN.

Test Steps:
1.  Send taprio cmd to board A:
    tc qdisc replace dev enp1s0 parent root handle 100 taprio \
    num_tc 4 \
    map 3 2 1 0 3 3 3 3 3 3 3 3 3 3 3 3 \
    queues 1@0 1@1 1@2 1@3 \
    base-time 0 \
    sched-entry S 0x07 500000 \
    sched-entry S 0x0f 500000 \
    flags 0x2 \
    txtime-delay 0

    Note that for TC3, gate should open for 500us and close for another
    500us.

3.  Take tcpdump log on Board B.

4.  Send udp packets via UDP tai app from Board A to Board B.

5.  Analyze tcpdump log via wireshark log on Board B. Ensure that the
    total time from the first to the last packet received during one cycle
    for TC3 does not exceed 500us.

Fixes: 4354621173 ("igc: Add new device ID's")
Signed-off-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Tested-by: Mor Bar-Gabay <morx.bar.gabay@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-29 17:33:17 +02:00
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block block: fix deadlock between sd_remove & sd_release 2024-08-03 08:54:24 +02:00
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crypto crypto: aead,cipher - zeroize key buffer after use 2024-07-11 12:49:04 +02:00
Documentation mm/page_table_check: support userfault wr-protect entries 2024-08-19 06:04:29 +02:00
drivers igc: Fix packet still tx after gate close by reducing i226 MAC retry buffer 2024-08-29 17:33:17 +02:00
fs btrfs: tree-checker: add dev extent item checks 2024-08-29 17:33:16 +02:00
include bpf: Fix updating attached freplace prog in prog_array map 2024-08-29 17:33:17 +02:00
init rust: SHADOW_CALL_STACK is incompatible with Rust 2024-08-11 12:47:24 +02:00
io_uring io_uring: fix io_match_task must_hold 2024-08-03 08:54:41 +02:00
ipc sysctl: treewide: drop unused argument ctl_table_root::set_ownership(table) 2024-08-11 12:47:13 +02:00
kernel bpf: Avoid kfree_rcu() under lock in bpf_lpm_trie. 2024-08-19 06:04:27 +02:00
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mm memcg_write_event_control(): fix a user-triggerable oops 2024-08-29 17:33:16 +02:00
net fou: remove warn in gue_gro_receive on unsupported protocol 2024-08-19 06:04:30 +02:00
rust rust: kernel: require Send for Module implementations 2024-05-17 12:01:56 +02:00
samples bpf: Replace bpf_lpm_trie_key 0-length array with flexible array 2024-08-19 06:04:27 +02:00
scripts kbuild: avoid build error when single DTB is turned into composite DTB 2024-08-03 08:54:36 +02:00
security selinux: add the processing of the failure of avc_add_xperms_decision() 2024-08-29 17:33:15 +02:00
sound ALSA: hda/tas2781: fix wrong calibrated data order 2024-08-29 17:33:12 +02:00
tools rtla/osnoise: Prevent NULL dereference in error handling 2024-08-29 17:33:14 +02:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin() 2024-06-27 13:49:11 +02:00
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COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
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MAINTAINERS pwm: Rename pwm_apply_state() to pwm_apply_might_sleep() 2024-06-12 11:12:24 +02:00
Makefile Linux 6.6.47 2024-08-19 06:04:32 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.