On Fri, 18 Jul 2025, Shuai Xue wrote: > 在 2025/7/18 11:46, Matthew W Carlis 写道: > > On Thu, Jul 17, 2025 Bjorn Helgaas wrote > > > So I think your idea of adding current link speed/width to the "Link > > > Up" event is still on the table, and that does sound useful to me. > > > > We're already reading the link status register here to check DLLA so > > it would be nice. I guess if everything is healthy we're probably already > > at the maximum speed by this point. > > > > > In the future we might add another tracepoint when we enumerate the > > > device and know the Vendor/Device ID. > > > > I think we might have someone who would be interested in doing it. > > > Hi, all, > > IIUC, the current hotplug event (or presence event) is enough for Matthew. > and we would like a new tracepoing for link speed change which reports > speeds. > > For hotplug event, I plan to send a new version to > > 1. address Bjorn' concerns about event strings by removing its spaces. > > #define PCI_HOTPLUG_EVENT > \ > EM(PCI_HOTPLUG_LINK_UP, "PCI_HOTPLUG_LINK_UP") > \ > EM(PCI_HOTPLUG_LINK_DOWN, "PCI_HOTPLUG_LINK_DOWN") > \ > EM(PCI_HOTPLUG_CARD_PRESENT, "PCI_HOTPLUG_CARD_PRESENT") > \ > EMe(PCI_HOTPLUG_CARD_NOT_PRESENT, > "PCI_HOTPLUG_CARD_NOT_PRESENT") > > 2. address Ilpo comments by moving pci_hp_event to a common place > (include/trace/events/pci.h) so that the new comming can also use it.
Ah, I only now noticed you've decided to re-place them. Please disregard my other comment about this being still open/undecided item. > For link speed change event (perhaps named as pci_link_event), > I plan to send a seperate patch, which provides: > > TP_STRUCT__entry( > __string( port_name, port_name ) > __field( unsigned char, cur_bus_speed ) > __field( unsigned char, max_bus_speed ) > __field( unsigned char, width ) > __field( unsigned int, flit_mode ) > __field( unsigned char, reason ) > ), > > The reason field is from Lukas ideas which indicates why the link speed > changed, e.g. "hotplug", "autonomous", "thermal", "retrain", etc. > > Are you happy with above changes? Since you're probably quite far with the pcie link event patch too given above, could you take a look at the LNKSTA flags representation in my patch and incorporate those as well as there seems to always lot of uncertainty about those flags when investigating the LBMS/bwctrl related issues so it seems prudent to explicitly include them into the traceevent output: https://lore.kernel.org/linux-pci/7c289bba-3133-0989-6333-41fc41fe3...@linux.intel.com/ -- i.
