On 10/1/19 4:14 PM, Stuart Hayes wrote:
Some systems have in-band presence detection disabled for hot-plug PCI slots,
but do not report this in the slot capabilities 2 (SLTCAP2) register. On
these systems, presence detect can become active well after the link is
reported to be active, which can cause the slots to be disabled after a
device is connected.
Add a dmi table to flag these systems as having in-band presence disabled.
Signed-off-by: Stuart Hayes <stuart.w.hayes@xxxxxxxxx>
---
drivers/pci/hotplug/pciehp_hpc.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 1282641c6458..1dd01e752587 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -14,6 +14,7 @@
#define dev_fmt(fmt) "pciehp: " fmt
+#include <linux/dmi.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/jiffies.h>
@@ -26,6 +27,16 @@
#include "../pci.h"
#include "pciehp.h"
+static const struct dmi_system_id inband_presence_disabled_dmi_table[] = {
+ {
+ .ident = "Dell System",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc"),
+ },
+ },
+ {}
+};
+
I'm not sure that all Dell systems that were ever made or will be made
have in-band presence disabled on all their hotplug slots.
This was a problem with the NVMe hot-swap bays on 14G servers. I can't
guarantee that any other slot or machine will need this workaround. The
best way I found to implement this is to check for the PCI-ID of the
switches behind the port.
Alex
