On Fri, 9 Aug 2024, Maciej W. Rozycki wrote: > On Wed, 7 Feb 2024, Ilpo Järvinen wrote: > > > > > > Because if it is constantly picking another speed, it would mean you get > > > > > LBMS set over and over again, no? If that happens 34-35 times per second, > > > > > it should be set already again when we get into that quirk because there > > > > > was some wait before it gets called. > > > > > > > > I'll see if I can experiment with the hardware over the next couple of > > > > days and come back with my findings. > > > > > > Okay thanks. > > > > One point I'd be very interested to know if the link actually comes up > > successfully (even if briefly) because this has large implications whether > > the quirk can actually be invoked from the bandwidth controller code. > > That was more than a couple of days, sorry about it. I have now been > able to verify that LBMS keeps getting reasserted over and over again as > the device goes through the infinite link training dance. I haven't ever > observed the link to become active in the course. Here's a short log of > commands repeatedly entered at the command prompt: > > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5011 > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5812 > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5811 > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5812 > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5011 > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5811 > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5811 > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5812 > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5812 > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5811 > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5811 > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5812 > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5812 > # setpci -s 02:03.0 CAP_EXP+0x12.W > 5811 > > As you can see the Link Training bit oscillates as I previously reported > and noted in the introduction to `pcie_failed_link_retrain', and also the > Current Link Speed field flips between 2.5GT/s and 5GT/s. Okay, thanks for testing. I suppose that test wasn't done in a busy loop (it might not be easy capture very short link up state if there was any such period when testing it by manually launching that command a few times)? -- i.
