lkml.org 
[lkml]   [2018]   [Aug]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: lspci: Display path to device
Hello!

> I don't like telling the user to grovel around lspci -t by hand. It's
> not many lines of code to add a new -P option to lspci to show the path
> to each device instead of bus:dev.fn

I like the feature, but I have a couple of minor objections to the
implementation:

> -static char options[] = "nvbxs:d:ti:mgp:qkMDQ" GENERIC_OPTIONS ;
> +static char options[] = "nvbxs:d:tPi:mgp:qkMDQ" GENERIC_OPTIONS ;

Please update the help_msg, too.

> +static void
> +show_slot_path(struct pci_dev *p)
> +{
> + struct pci_dev *d = NULL;
> +
> + if (opt_path && p->bus)
> + {
> + for (d = p->access->devices; d; d = d->next) {
> + if (d->hdrtype == -1)
> + d->hdrtype = pci_read_byte(d, PCI_HEADER_TYPE) & 0x7f;

Please do not modify the hdrtype field, it is private to libpci.

Instead, always read the PCI_HEADER_TYPE register. It will be fast since
lspci caches configuration space accesses.

> + if (d->hdrtype != PCI_HEADER_TYPE_BRIDGE &&
> + d->hdrtype != PCI_HEADER_TYPE_CARDBUS)
> + continue;
> + if (pci_read_byte(d, PCI_SECONDARY_BUS) > p->bus)
> + continue;
> + if (pci_read_byte(d, PCI_SUBORDINATE_BUS) < p->bus)
> + continue;

Beware, cardbus bridges use different registers for secondary and subordinate bus.

... the more I think about it, the more I am convinced that we want to
re-use the bus topology builder from ls-tree.c. I will give it a try,
stay tuned.

Martin

\
 
 \ /
  Last update: 2018-08-10 11:41    [W:0.115 / U:44.168 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site