On Wed, Nov 20, 2024 at 10:32:32PM +0530, Manivannan Sadhasivam wrote:
> On Wed, Nov 20, 2024 at 10:10:47AM -0600, Bjorn Helgaas wrote:
> > On Fri, Oct 25, 2024 at 01:24:53PM +0530, Manivannan Sadhasivam via B4 Relay wrote:
> > > From: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> > >
> > > As per the kernel device driver model, pwrctl device is the supplier for
> > > the PCI device. But the device link that enforces the supplier-consumer
> > > relationship is created inside the pwrctl driver currently. Due to this,
> > > the driver model doesn't prevent probing of the PCI client drivers before
> > > probing the corresponding pwrctl drivers. This may lead to a race condition
> > > if the PCI device was already powered on by the bootloader (before the
> > > pwrctl driver).
> >
> > > + * Create a device link between the PCI device and pwrctl device (if
> > > + * exists). This ensures that the pwrctl drivers are probed before the
> > > + * PCI client drivers.
> > > + */
> > > + pdev = of_find_device_by_node(dn);
> > > + if (pdev) {
> > > + if (!device_link_add(&dev->dev, &pdev->dev, DL_FLAG_AUTOREMOVE_CONSUMER))
> > > + pci_err(dev, "failed to add device link between %s and %s\n",
> > > + dev_name(&dev->dev), pdev->name);
> >
> > This prints the name for "dev" twice (once by pci_err(dev) and again
> > from dev_name(&dev->dev)). Is it helpful to see it twice here?
>
> Hmm, not very much. It could be reworded as below:
>
> pci_err(dev, "failed to link: %s\n", pdev->name);
OK. I updated the comment and the message like this (also renamed
of_pci_is_supply_present() to of_pci_supply_present() so it reads more
naturally in "if" statements):
- * Create a device link between the PCI device and pwrctrl device (if
- * exists). This ensures that the pwrctrl drivers are probed before the
- * PCI client drivers.
+ * If the PCI device is associated with a pwrctrl device with a
+ * power supply, create a device link between the PCI device and
+ * pwrctrl device. This ensures that pwrctrl drivers are probed
+ * before PCI client drivers.
*/
pdev = of_find_device_by_node(dn);
- if (pdev) {
+ if (pdev && of_pci_supply_present(dn)) {
if (!device_link_add(&dev->dev, &pdev->dev,
DL_FLAG_AUTOREMOVE_CONSUMER))
- pci_err(dev, "failed to add device link between %s and %s\n",
- dev_name(&dev->dev), pdev->name);
+ pci_err(dev, "failed to add device link to power control device %s\n",
+ pdev->name);
}
