[PATCH] pciehp: Add pciehp_surprise module option

[Takashi Iwai]

We encountered a problem that on some HP machines the Realtek PCI-e
card reader device appears only when you inserted a card before the
cold boot.  While debugging, it turned out that the device is actually
handled via PCI-e hotplug in some level.  The device sends a presence
change notification, and pciehp receives it, but it's ignored because
of lack of the hotplug surprise (PCI_EXP_SLTCAP_HPS) capability bit.
Once when this check passes, everything starts working -- the device
appears upon plugging the card properly.

There are a few other bug reports indicating the similar problems
(e.g. on recent Dell laptops), and I guess the culprit is same.

This patch adds a new module option, pciehp_surprise, to pciehp as a
workaround.  When pciehp_surprise=1 is given, pciehp handles the
presence change as the device on/off as if PCI_EXP_SLTCAP_HPS is set.
Unless it's set explicitly, there is no impact on the existing
behavior.

Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
 drivers/pci/hotplug/pciehp.h      | 3 ++-
 drivers/pci/hotplug/pciehp_core.c | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index 2c113de..314f3be 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -44,6 +44,7 @@ extern bool pciehp_poll_mode;
 extern int pciehp_poll_time;
 extern bool pciehp_debug;
 extern bool pciehp_force;
+extern bool pciehp_surprise;
 
 #define dbg(format, arg...)						\
 do {									\
@@ -122,7 +123,7 @@ struct controller {
 #define MRL_SENS(ctrl)		((ctrl)->slot_cap & PCI_EXP_SLTCAP_MRLSP)
 #define ATTN_LED(ctrl)		((ctrl)->slot_cap & PCI_EXP_SLTCAP_AIP)
 #define PWR_LED(ctrl)		((ctrl)->slot_cap & PCI_EXP_SLTCAP_PIP)
-#define HP_SUPR_RM(ctrl)	((ctrl)->slot_cap & PCI_EXP_SLTCAP_HPS)
+#define HP_SUPR_RM(ctrl)	(pciehp_surprise || ((ctrl)->slot_cap & PCI_EXP_SLTCAP_HPS))
 #define EMI(ctrl)		((ctrl)->slot_cap & PCI_EXP_SLTCAP_EIP)
 #define NO_CMD_CMPL(ctrl)	((ctrl)->slot_cap & PCI_EXP_SLTCAP_NCCS)
 #define PSN(ctrl)		((ctrl)->slot_cap >> 19)
diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index 7d72c5e..c3a574e 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -42,6 +42,7 @@ bool pciehp_debug;
 bool pciehp_poll_mode;
 int pciehp_poll_time;
 bool pciehp_force;
+bool pciehp_surprise;
 
 #define DRIVER_VERSION	"0.4"
 #define DRIVER_AUTHOR	"Dan Zink <dan.zink@xxxxxxxxxx>, Greg Kroah-Hartman <greg@xxxxxxxxx>, Dely Sy <dely.l.sy@xxxxxxxxx>"
@@ -55,10 +56,12 @@ module_param(pciehp_debug, bool, 0644);
 module_param(pciehp_poll_mode, bool, 0644);
 module_param(pciehp_poll_time, int, 0644);
 module_param(pciehp_force, bool, 0644);
+module_param(pciehp_surprise, bool, 0644);
 MODULE_PARM_DESC(pciehp_debug, "Debugging mode enabled or not");
 MODULE_PARM_DESC(pciehp_poll_mode, "Using polling mechanism for hot-plug events or not");
 MODULE_PARM_DESC(pciehp_poll_time, "Polling mechanism frequency, in seconds");
 MODULE_PARM_DESC(pciehp_force, "Force pciehp, even if OSHP is missing");
+MODULE_PARM_DESC(pciehp_surprise, "Force to set hotplug-surprise capability");
 
 #define PCIE_MODULE_NAME "pciehp"
 
-- 
1.8.2

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