On Wed, Nov 20, 2024 at 02:18:39PM -0600, Bjorn Helgaas wrote:
> 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",
Maybe use 'pwrctrl' instead of 'power control'?
- Mani
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