On 02/21/2014 09:51 AM, Matthew Garrett wrote: > On Fri, 2014-02-21 at 07:37 -0600, Corey Minyard wrote: > >> However, the basic problem is that hardware vendors produce hardware >> that sucks and then expect software to fix all the problems. Most IPMI >> interfaces don't have interrupts, so they have to be polled. Then they >> add important interfaces on top of it like firmware upgrade and ACPI and >> expect it to perform well. If vendors would just have an interrupt for >> IPMI, 99% of these problems would go away. > Not going to disagree. The impact on power consumption is also pretty > awful. I should re-read the spec to figure out whether we can > legitimately get away with not doing that.
Thinking about this some more, I realized that it may possible to turn off the driver if nothing at all is waiting. I'll need to look at the spec to see if I'm forgetting something. > >> One thing we can do is remove the default interface probing for IPMI. >> Even though the spec has it, all modern hardware should have it >> specified in ACPI or device tree. That should fix all the slow boot >> problems, at least. If a user wants to add a default interface, they >> can use the interface to dynamically add it after boot time. > Something like this (untested)? That's exactly what I would have done... -corey > > diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig > index eea8464..5126230 100644 > --- a/drivers/char/ipmi/Kconfig > +++ b/drivers/char/ipmi/Kconfig > @@ -52,6 +52,16 @@ config IPMI_SI > Currently, only KCS and SMIC are supported. If > you are using IPMI, you should probably say "y" here. > > +config IPMI_PROBE_DEFAULTS > + bool 'Probe for all possible IPMI interfaces by default' > + help > + Modern systems will usually expose IPMI interfaces via a > discoverable > + firmware mechanism such as ACPI or DMI. Older systems do not, and so > + the driver is forced to probe hardware manually. This may cause boot > + delays. Say "n" here to disable this manual probing. IPMI will then > + only be available on older systems if the > "ipmi_si_intf.trydefaults=1" > + boot argument is passed. > + > config IPMI_WATCHDOG > tristate 'IPMI Watchdog Timer' > help > diff --git a/drivers/char/ipmi/ipmi_si_intf.c > b/drivers/char/ipmi/ipmi_si_intf.c > index 03f4189..82c7d56 100644 > --- a/drivers/char/ipmi/ipmi_si_intf.c > +++ b/drivers/char/ipmi/ipmi_si_intf.c > @@ -1230,7 +1230,11 @@ static bool si_tryplatform = 1; > #ifdef CONFIG_PCI > static bool si_trypci = 1; > #endif > +#ifdef CONFIG_IPMI_PROBE_DEFAULTS > static bool si_trydefaults = 1; > +#else > +static bool si_trydefaults; > +#endif > static char *si_type[SI_MAX_PARMS]; > #define MAX_SI_TYPE_STR 30 > static char si_type_str[MAX_SI_TYPE_STR]; > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
