On 31.05.22 23:31, Bjorn Helgaas wrote:
On Mon, May 30, 2022 at 10:32:06AM +0200, Pali Rohár wrote:
On Monday 30 May 2022 10:18:41 Stefan Roese wrote:
On 28.05.22 02:09, Bjorn Helgaas wrote:
In subject line, I assume you mean "System Errors" instead of "Service
Errors"?
Background: I took over submitting this patchset from Bharat. Here his
last revision:
https://www.spinics.net/lists/kernel/msg2960164.html
Here's the link to the more usable lore archive:
https://lore.kernel.org/all/1542206878-24587-1-git-send-email-bharat.kumar.gogada@xxxxxxxxxx/
To answer your question I personally think too, that "System Errors" is
more appropriate than "Service Errors". But still this patchset replaces
or better enhances the already present pcie_init_service_irqs() by a
platform-specific version. I can only suspect, that this is the
reasoning for this "Service" naming.
Hello! Based on the below text "Here the quote from Bharat's original
cover letter:" I think that the better naming should be: "Service
interrupts". Because it adds support for interrupts from PCIe services
like AER, PME or HP. Only AER are errors, other IRQs are just services.
The question I'm trying to answer is whether this series concerns the
"System Error" mechanism or the "Error Interrupt" mechanism. We
should figure out which one this is and use the correct name.
The sec 6.2.4.1.2 cited below clearly refers to the AER Root Error
Command register, which controls interrupt generation via INTx, MSI,
or MSI-X, i.e., the standard "Error Interrupt" shown on the RIGHT side
of Figure 6-3 in sec 6.2.6.
The "System Error" signaling on the LEFT side of Figure 6-3 would be
controlled by the Root Control register in the PCIe capability.
"System Error" is probably incorrect. You've already stated, that
these error bits are generally disabled in the PCI_EXP_RTCTL reg in
aer_enable_rootport():
/* Disable system error generation in response to error messages */
pcie_capability_clear_word(pdev, PCI_EXP_RTCTL,
SYSTEM_ERROR_INTR_ON_MESG_MASK);
This leaves "Error Interrupt", but I might be wrong here.
It should be easy to use setpci to set/clear these two sets of enable
bits and figure out which path is of interest here.
Here the value of the PCI_EXP_RTCTL register at runtime:
# setpci -v -s 00:00.0 CAP_EXP+0x1c.w
0000:00:00.0 (cap 10 @60) @7c = 0010
So all "System Error" enable bits are disabled.
Please let me know if I should make some other "setpci" tests.
On Fri, Jan 14, 2022 at 08:58:33AM +0100, Stefan Roese wrote:
From: Bharat Kumar Gogada <bharat.kumar.gogada@xxxxxxxxxx>
As per section 6.2.4.1.2, 6.2.6 in PCIe r4.0 (and later versions),
platform-specific System Errors like AER can be delivered via platform-
specific interrupt lines.
...
6.7.3.4 ("Software Notification of Hot-Plug Events") talks about PME
and Hot-Plug Event interrupts, but these aren't errors, and I only see
signaling via INTx, MSI, or MSI-X. Is there provision for a different
method?
Here the quote from Bharat's original cover letter:
"Some platforms have dedicated IRQ lines for PCIe services like AER/PME
etc. The root complex on these platform will use these seperate IRQ
lines to report AER/PME etc., interrupts and will not generate MSI/
MSI-X/INTx interrupts for these services.
This is the best explanation of this change.
As far as I can tell, "dedicated IRQ lines for services like AER/PME
etc" would violate the PCIe spec.
AFAICT this is the case here.
That's OK, we can work around that
sort of thing, but it needs to be clearly called out as some kind of
quirk and not mixed in with things like System Error signaling, which
is allowed to be platform-specific.
Agreed. So how to process with this patchset? Should I reword the
patch subject line (and the commit text and comments) to something like:
Add option to setup IRQs for platform-specific Error Interrupt ?
Thanks,
Stefan
