On 1/6/25 12:53, Bjorn Helgaas wrote:
On Mon, Jan 06, 2025 at 12:34:00PM -0800, Tushar Dave wrote:
On 1/2/25 10:40, Jason Gunthorpe wrote:
On Fri, Dec 13, 2024 at 12:29:42PM -0800, Tushar Dave wrote:
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index dc663c0ca670..fc1c37910d1c 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4654,11 +4654,10 @@
Format:
<ACS flags>@<pci_dev>[; ...]
Specify one or more PCI devices (in the format
- specified above) optionally prepended with flags
- and separated by semicolons. The respective
- capabilities will be enabled, disabled or
- unchanged based on what is specified in
- flags.
+ specified above) prepended with flags and separated
+ by semicolons. The respective capabilities will be
+ enabled, disabled or unchanged based on what is
+ specified in flags.
ACS Flags is defined as follows:
bit-0 : ACS Source Validation
@@ -4673,7 +4672,7 @@
'1' – force enabled
'x' – unchanged
For example,
- pci=config_acs=10x
+ pci=config_acs=10x@pci:0:0
would configure all devices that support
ACS to enable P2P Request Redirect, disable
Translation Blocking, and leave Source
Is this an unrelated change? The format of the command line shouldn't
be changed to fix the described bug, why is the documentation changed?
The documentation as it is (i.e. without my patch), is not correct.
IOW, config_acs parameter does require flags and it is not optional. Without
flags it results into "ACS Flags missing". Therefore I remove word
"optionally" from the documentation text.
Secondly, the syntax in the example 'pci=config_acs=10x' is incorrect. The
correct syntax should be 'pci=config_acs=10x@pci:0:0' that would configure
all devices that support ACS to enable P2P Request Redirect, disable
Translation Blocking, and leave Source Validation unchanged from whatever
power-up or firmware set it to.
I'd suggest a separate patch to fix the documentation so we don't try
to relate the doc changes with the code changes.
Sure thing. I will send a separate patch for the doc changes.
-Tushar
