At Wed, 20 Mar 2013 09:33:18 -0700, Randy Dunlap wrote: > > On 03/20/13 07:02, Takashi Iwai wrote: > > 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_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 > > @@ -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"); > > > It appears that all of the pciehp options need to be documented, > preferably in Documentation/kernel-parameters.txt . Yeah, makes sense. Off-topic: it would have been nicer if pciehp_ prefix was removed at the first place, too. But it's too late and we need to live with it. Takashi -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
