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Miller" , Eric Dumazet , Furong Xu <0x1207@gmail.com>, Jacob Keller , Jakub Kicinski , "Jan Petrous (OSS)" , linux-arm-kernel@lists.infradead.org, linux-stm32@st-md-mailman.stormreply.com, Maxime Chevallier , Maxime Coquelin , netdev@vger.kernel.org, Paolo Abeni , Simon Horman , Yu-Chun Lin Subject: Re: [PATCH net-next 0/3] net: stmmac: phylink PCS conversion part 3 (dodgy stuff) Message-ID: References: <20251103104820.3fcksk27j34zu6cg@skbuf> <20251103121353.dbnalfub5mzwad62@skbuf> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251103121353.dbnalfub5mzwad62@skbuf> X-Authority-Analysis: v=2.4 cv=OrdCCi/t c=1 sm=1 tr=0 ts=6908c082 cx=c_pps a=oF/VQ+ItUULfLr/lQ2/icg==:117 a=ZePRamnt/+rB5gQjfz0u9A==:17 a=kj9zAlcOel0A:10 a=6UeiqGixMTsA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=8AirrxEcAAAA:8 a=h6mluUUUhvrYO4b4W1oA:9 a=CjuIK1q_8ugA:10 a=3WC7DwWrALyhR5TkjVHa:22 a=ST-jHhOKWsTCqRlWije3:22 X-Proofpoint-ORIG-GUID: 8iimeR2N6CgwDjCkoC6lMvx1ZjKxtgbF X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTAzMDEzNCBTYWx0ZWRfX41ZXYtuePeBW LAan5gEaNIhDOQV8aGC8rVKw4wsLgGa0Nokz/P1gNSAtNGEkhqTBIm5MVQi2aWAClCCpYtdU3lM fGrpL5MaWT9BXCOTd9Qc1vLPPHpjrJTCs896fWN0OwE7RV6z3fbi9yKEHjeB4duvmFLaz5cir17 lyFck6H3CTaXtu4ikd041cL84UObbUYRAnWPchLhxQ8QKiHAagtA3+h5phe5paEYVmyCRf/2yGr VQofk4H/s/+qoQlsn8OKYXCnRhgWnugRijMMd4DG+4PzI457DSk8e5ul1oob+KSEP6ifP/rxB3x GHOXHQbMnsHhwG0et31LSeqbsGNQaeqJugyMNfQ1BB81NyrWpPucdEJeqxmH7IEZsIw2hP8AeTl zLOhHlXOobrjsACrjvCvGWqpVCWwIA== X-Proofpoint-GUID: 8iimeR2N6CgwDjCkoC6lMvx1ZjKxtgbF X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-03_02,2025-11-03_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 adultscore=0 lowpriorityscore=0 priorityscore=1501 malwarescore=0 suspectscore=0 bulkscore=0 impostorscore=0 phishscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2510240001 definitions=main-2511030134 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251103_064731_125707_506ACDC7 X-CRM114-Status: GOOD ( 51.72 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Nov 03, 2025 at 02:13:53PM +0200, Vladimir Oltean wrote: > On Mon, Nov 03, 2025 at 11:43:23AM +0000, Russell King (Oracle) wrote: > > On Mon, Nov 03, 2025 at 04:50:03PM +0530, Mohd Ayaan Anwar wrote: > > > On Mon, Nov 03, 2025 at 12:48:20PM +0200, Vladimir Oltean wrote: > > > > > > > > As Russell partially pointed out, there are several assumptions in the > > > > Aquantia PHY driver and in phylink, three of them being that: > > > > - rate matching is only supported for PHY_INTERFACE_MODE_10GBASER and > > > > PHY_INTERFACE_MODE_2500BASEX (thus not PHY_INTERFACE_MODE_SGMII) > > > > - if phy_get_rate_matching() returns RATE_MATCH_NONE for an interface, > > > > pl->phy_state.rate_matching will also be RATE_MATCH_NONE when using > > > > that interface > > > > - if rate matching is used, the PHY is configured to use it for all > > > > media speeds <= phylink_interface_max_speed(link_state.interface) > > > > > > > > Those assumptions are not validated very well against the ground truth > > > > from the PHY provisioning, so the next step would be for us to see that > > > > directly. > > > > > > > > Please turn this print from aqr_gen2_read_global_syscfg() into something > > > > visible in dmesg, i.e. by replacing phydev_dbg() with phydev_info(): > > > > > > > > phydev_dbg(phydev, > > > > "Media speed %d uses host interface %s with %s\n", > > > > syscfg->speed, phy_modes(syscfg->interface), > > > > syscfg->rate_adapt == AQR_RATE_ADAPT_NONE ? "no rate adaptation" : > > > > syscfg->rate_adapt == AQR_RATE_ADAPT_PAUSE ? "rate adaptation through flow control" : > > > > syscfg->rate_adapt == AQR_RATE_ADAPT_USX ? "rate adaptation through symbol replication" : > > > > "unrecognized rate adaptation type"); > > > > > > Thanks. Looks like rate adaptation is only provisioned for 10M, which > > > matches my observation where phylink passes the exact speeds for > > > 100/1000/2500 but 1000 for 10M. > > > > Hmm, I wonder what the PHY is doing for that then. stmmac will be > > programmed to read the Cisco SGMII in-band control word, and use > > that to determine whether symbol replication for slower speeds is > > being used. > > > > If AQR115C is indicating 10M in the in-band control word, but is > > actually operating the link at 1G speed, things are not going to > > work, and I would say the PHY is broken to be doing that. The point > > of the SGMII in-band control word is to tell the MAC about the > > required symbol replication on the link for transmitting the slower > > data rates over the link. > > > > stmmac unfortunately doesn't give access to the raw Cisco SGMII > > in-band control word. However, reading register 0xf8 bits 31:16 for > > dwmac4, or register 0xd8 bits 15:0 for dwmac1000 will give this > > information. In that bitfield, bits 2:1 give the speed. 2 = 1G, > > 1 = 100M, 0 = 10M. > > It might be Linux who is forcing the AQR115C into the nonsensical > behaviour of advertising 10M in the SGMII control word while > simultanously forcing the PHY MII to operate at 1G with flow control > for the 10M media speed. > > We don't control the latter, but we do control the former: > aqr_gen2_config_inband(), if given modes == LINK_INBAND_ENABLE, will > enable in-band for all media speeds that use PHY_INTERFACE_MODE_SGMII. > Regardless of how the PHY was provisioned for each media speed, and > especially regardless of rate matching settings, this function will > uniformly set the same in-band enabled/disabled setting for all media > speeds using the same host interface. > > If dwmac_integrated_pcs_inband_caps(), as per Russell's patch 1/3, > reports LINK_INBAND_ENABLE | LINK_INBAND_DISABLE, and if > aqr_gen2_inband_caps() also reports LINK_INBAND_ENABLE | LINK_INBAND_DISABLE, > then we're giving phylink_pcs_neg_mode() all the tools it needs to shoot > itself in the foot, and select LINK_INBAND_ENABLE. > > The judgement call in the Aquantia PHY driver was mine, as documented in > commit 5d59109d47c0 ("net: phy: aquantia: report and configure in-band > autoneg capabilities"). The idea being that the configuration would have > been unsupportable anyway given the question that the framework asks: > "does the PHY use in-band for SGMII, or does it not?" > > Assuming the configuration at 10Mbps wasn't always broken, there's only > one way to know how it was supposed to work: more dumping of the initial > provisioning, prior to our modification in aqr_gen2_config_inband(). > Ayaan, please re-print the same info with this new untested patch applied. > I am going to assume that in-band autoneg isn't enabled in the unmodified > provisioning, at least for 10M. > > Russell's request for the integrated PCS status is also a good parallel > confirmation that yes, we've entered a mode where the PHY advertises > SGMII replication at 10M. > From b91162e5dae8e20b477999c4f2fcdb98c219d663 Mon Sep 17 00:00:00 2001 > From: Vladimir Oltean > Date: Mon, 3 Nov 2025 14:03:55 +0200 > Subject: [PATCH] net: phy: aquantia: add inband setting to the > aqr_gen2_read_global_syscfg() print > > Signed-off-by: Vladimir Oltean > --- > drivers/net/phy/aquantia/aquantia_main.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/phy/aquantia/aquantia_main.c b/drivers/net/phy/aquantia/aquantia_main.c > index 41f3676c7f1e..f06b7b51bb7d 100644 > --- a/drivers/net/phy/aquantia/aquantia_main.c > +++ b/drivers/net/phy/aquantia/aquantia_main.c > @@ -839,6 +839,7 @@ static int aqr_gen2_read_global_syscfg(struct phy_device *phydev) > > for (i = 0; i < AQR_NUM_GLOBAL_CFG; i++) { > struct aqr_global_syscfg *syscfg = &priv->global_cfg[i]; > + bool inband; > > syscfg->speed = aqr_global_cfg_regs[i].speed; > > @@ -849,6 +850,7 @@ static int aqr_gen2_read_global_syscfg(struct phy_device *phydev) > > serdes_mode = FIELD_GET(VEND1_GLOBAL_CFG_SERDES_MODE, val); > rate_adapt = FIELD_GET(VEND1_GLOBAL_CFG_RATE_ADAPT, val); > + inband = FIELD_GET(VEND1_GLOBAL_CFG_AUTONEG_ENA, val); > > switch (serdes_mode) { > case VEND1_GLOBAL_CFG_SERDES_MODE_XFI: > @@ -896,12 +898,13 @@ static int aqr_gen2_read_global_syscfg(struct phy_device *phydev) > } > > phydev_dbg(phydev, > - "Media speed %d uses host interface %s with %s\n", > + "Media speed %d uses host interface %s with %s, inband %s\n", > syscfg->speed, phy_modes(syscfg->interface), > syscfg->rate_adapt == AQR_RATE_ADAPT_NONE ? "no rate adaptation" : > syscfg->rate_adapt == AQR_RATE_ADAPT_PAUSE ? "rate adaptation through flow control" : > syscfg->rate_adapt == AQR_RATE_ADAPT_USX ? "rate adaptation through symbol replication" : > - "unrecognized rate adaptation type"); > + "unrecognized rate adaptation type", > + str_enabled_disabled(inband)); > } > > return 0; > -- > 2.43.0 > Here are the logs when I boot up with a 10M link: [ 10.743044] Aquantia AQR115C stmmac-0:08: Media speed 10 uses host interface sgmii with rate adaptation through flow control, inband enabled [ 10.757965] Aquantia AQR115C stmmac-0:08: Media speed 100 uses host interface sgmii with no rate adaptation, inband enabled [ 10.769857] Aquantia AQR115C stmmac-0:08: Media speed 1000 uses host interface sgmii with no rate adaptation, inband enabled [ 10.781840] Aquantia AQR115C stmmac-0:08: Media speed 2500 uses host interface 2500base-x with no rate adaptation, inband disabled [ 10.794346] Aquantia AQR115C stmmac-0:08: Media speed 5000 uses host interface 10gbase-r with rate adaptation through flow control, inband disabled [ 10.808358] Aquantia AQR115C stmmac-0:08: Media speed 10000 uses host interface 10gbase-r with no rate adaptation, inband disabled [ 10.827242] qcom-ethqos 23040000.ethernet eth1: PHY stmmac-0:08 uses interfaces 4,23,27, validating 23 [ 10.836812] qcom-ethqos 23040000.ethernet eth1: interface 23 (2500base-x) rate match pause supports 0-7,9,13-14,47 [ 10.836817] qcom-ethqos 23040000.ethernet eth1: PHY [stmmac-0:08] driver [Aquantia AQR115C] (irq=318) [ 10.836819] qcom-ethqos 23040000.ethernet eth1: phy: 2500base-x setting supported 0000000,00000000,00008000,000062ff advertising 0000000,00000000,00008000,000062ff [ 10.851865] qcom-ethqos 23040000.ethernet eth1: Enabling Safety Features [ 10.882611] qcom-ethqos 23040000.ethernet eth1: IEEE 1588-2008 Advanced Timestamp supported [ 10.895207] qcom-ethqos 23040000.ethernet eth1: registered PTP clock [ 10.902334] qcom-ethqos 23040000.ethernet eth1: configuring for phy/2500base-x link mode [ 10.910654] qcom-ethqos 23040000.ethernet eth1: major config, requested phy/2500base-x [ 10.918790] qcom-ethqos 23040000.ethernet eth1: has pcs = true [ 10.924787] qcom-ethqos 23040000.ethernet eth1: interface 2500base-x inband modes: pcs=01 phy=00 [ 10.933809] qcom-ethqos 23040000.ethernet eth1: major config, active phy/outband/2500base-x [ 10.942388] qcom-ethqos 23040000.ethernet eth1: phylink_mac_config: mode=phy/2500base-x/none adv=0000000,00000000,00000000,00000000 pause=00 [ 10.966344] qcom-ethqos 23040000.ethernet eth1: phy link down 2500base-x/Unknown/Unknown/none/off/nolpi [ 12.819779] qcom-ethqos 23040000.ethernet eth1: phy link up sgmii/10Mbps/Half/pause/off/nolpi [ 12.825947] stmmac_pcs: Link Down [ 12.829539] qcom-ethqos 23040000.ethernet eth1: major config, requested phy/sgmii [ 12.831998] stmmac_pcs: Link Down [ 12.839683] qcom-ethqos 23040000.ethernet eth1: has pcs = true [ 12.843123] stmmac_pcs: Link Down [ 12.849121] qcom-ethqos 23040000.ethernet eth1: interface sgmii inband modes: pcs=03 phy=03 [ 12.852546] stmmac_pcs: Link Down [ 12.861109] qcom-ethqos 23040000.ethernet eth1: major config, active phy/outband/sgmii [ 12.864535] stmmac_pcs: Link Down [ 12.872724] qcom-ethqos 23040000.ethernet eth1: phylink_mac_config: mode=phy/sgmii/pause adv=0000000,00000000,00000000,00000000 pause=00 [ 12.876094] stmmac_pcs: Link Down [ 12.891394] qcom-ethqos 23040000.ethernet eth1: ethqos_configure_sgmii : Speed = 1000 [ 12.892094] stmmac_pcs: Link Down [ 12.900109] dwmac: PCS configuration changed from phylink by glue, please report: 0x00040000 -> 0x00041200 [ 12.903555] stmmac_pcs: Link Up [ 12.913473] qcom-ethqos 23040000.ethernet eth1: Link is Up - 10Mbps/Half - flow control off [ 12.916679] stmmac_pcs: Link Down [ 12.928659] stmmac_pcs: ANE process completed [ 12.933133] stmmac_pcs: Link Up Although unrelated, I found it weird that the link comes up in half duplex mode for 10M. To enable full duplex, I have to manually do it via ethtool. I will try to connect a different link partner tomorrow, just to rule out any issues on the other end. Ayaan