Messages in this thread | | | Date | Thu, 24 Jun 2021 07:15:21 -0500 | From | Bjorn Helgaas <> | Subject | Re: [PATCH v7 4/8] PCI/sysfs: Allow userspace to query and set device reset mechanism |
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On Tue, Jun 08, 2021 at 11:18:53AM +0530, Amey Narkhede wrote: > Add reset_method sysfs attribute to enable user to > query and set user preferred device reset methods and > their ordering.
> + Writing the name or comma separated list of names of any of > + the device supported reset methods to this file will set the > + reset methods and their ordering to be used when resetting > + the device.
> + while ((name = strsep(&options, ",")) != NULL) { > + if (sysfs_streq(name, "")) > + continue; > + > + name = strim(name); > + > + for (i = 0; i < PCI_RESET_METHODS_NUM; i++) { > + if (reset_methods[i] && > + sysfs_streq(name, pci_reset_fn_methods[i].name)) { > + reset_methods[i] = prio--; > + break; > + } > + } > + > + if (i == PCI_RESET_METHODS_NUM) { > + kfree(options); > + return -EINVAL; > + } > + }
Asking again since we didn't get this clarified before. The above tells me that "reset_methods" allows the user to control the *order* in which we try reset methods.
Consider the following two uses:
(1) # echo bus,flr > reset_methods
(2) # echo flr,bus > reset_methods
Do these have the same effect or not?
If "reset_methods" allows control over the order, I expect them to be different: (1) would try a bus reset and, if the bus reset failed, an FLR, while (2) would try an FLR and, if the FLR failed, a bus reset.
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