On Wed, Sep 25, 2024 at 07:49:59AM +0200, Jiri Slaby wrote:
> On 25. 09. 24, 7:29, Jiri Slaby wrote:
> > On 25. 09. 24, 7:06, Jiri Slaby wrote:
> > > > @@ -1047,23 +1066,33 @@ static void pci_std_enable_acs(struct
> > > > pci_dev *dev)
> > > > */
> > > > static void pci_enable_acs(struct pci_dev *dev)
> > > > {
> > > > - if (!pci_acs_enable)
> > > > - goto disable_acs_redir;
> > > > + struct pci_acs caps;
> > > > + int pos;
> > > > +
> > > > + pos = dev->acs_cap;
> > > > + if (!pos)
> > > > + return;
>
> Ignore the previous post.
>
> The bridge has no ACS (see lspci below). So it used to be enabled by
> pci_quirk_enable_intel_pch_acs() by another registers.
Er, Ok, so it overrides the whole thing with
pci_dev_specific_acs_enabled() too..
> I am not sure how to fix this as we cannot have "caps" from these quirks, so
> that whole idea of __pci_config_acs() is nonworking for these quirks.
We just need to allow the quirk to run before we try to do anything
with the cap, which has probably always been a NOP anyhow.
Maybe like this?
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 7d85c04fbba2ae..225a6cd2e9ca3b 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1067,8 +1067,15 @@ static void pci_std_enable_acs(struct pci_dev *dev, struct pci_acs *caps)
static void pci_enable_acs(struct pci_dev *dev)
{
struct pci_acs caps;
+ bool enable_acs = false;
int pos;
+ /* If an iommu is present we start with kernel default caps */
+ if (pci_acs_enable) {
+ if (pci_dev_specific_enable_acs(dev))
+ enable_acs = true;
+ }
+
pos = dev->acs_cap;
if (!pos)
return;
@@ -1077,11 +1084,8 @@ static void pci_enable_acs(struct pci_dev *dev)
pci_read_config_word(dev, pos + PCI_ACS_CTRL, &caps.ctrl);
caps.fw_ctrl = caps.ctrl;
- /* If an iommu is present we start with kernel default caps */
- if (pci_acs_enable) {
- if (pci_dev_specific_enable_acs(dev))
- pci_std_enable_acs(dev, &caps);
- }
+ if (enable_acs)
+ pci_std_enable_acs(dev, &caps);
/*
* Always apply caps from the command line, even if there is no iommu.
