From: Stuart Hayes <stuart.w.hayes@gmail.com>
Date: Fri, 25 Oct 2019 15:00:47 -0400
Subject: PCI: pciehp: Add DMI table for in-band presence detection disabled
Git-commit: 0b382546d863f2f09eecaccda95a0b4bfd148f92
Patch-mainline: v5.7-rc1
References: bnc#1162576 jsc#SLE-11112
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 detect
disabled.
Link: https://lore.kernel.org/r/20191025190047.38130-4-stuart.w.hayes@gmail.com
Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/pci/hotplug/pciehp_hpc.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
--- 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 +27,24 @@
#include "../pci.h"
#include "pciehp.h"
+static const struct dmi_system_id inband_presence_disabled_dmi_table[] = {
+ /*
+ * Match all Dell systems, as some Dell systems have inband
+ * presence disabled on NVMe slots (but don't support the bit to
+ * report it). Setting inband presence disabled should have no
+ * negative effect, except on broken hotplug slots that never
+ * assert presence detect--and those will still work, they will
+ * just have a bit of extra delay before being probed.
+ */
+ {
+ .ident = "Dell System",
+ .matches = {
+ DMI_MATCH(DMI_OEM_STRING, "Dell System"),
+ },
+ },
+ {}
+};
+
static inline struct pci_dev *ctrl_dev(struct controller *ctrl)
{
return ctrl->pcie->port;
@@ -899,6 +918,9 @@ struct controller *pcie_init(struct pcie
ctrl->inband_presence_disabled = 1;
}
+ if (dmi_first_match(inband_presence_disabled_dmi_table))
+ ctrl->inband_presence_disabled = 1;
+
/* Check if Data Link Layer Link Active Reporting is implemented */
pcie_capability_read_dword(pdev, PCI_EXP_LNKCAP, &link_cap);