SMBus controller

[Warner Losh]

On Jun 14, 2014, at 4:43 PM, Sean Bruno <sbruno at ignoranthack.me> wrote:

> On Sat, 2014-06-14 at 12:08 -0700, Sean Bruno wrote: 
>> I note that my TLenovo 61 has one of these:
>> 
>> ichsmb0 at pci0:0:31:3:	class=0x0c0500 card=0x20a917aa chip=0x283e8086
>> rev=0x03 hdr=0x00
>>    vendor     = 'Intel Corporation'
>>    device     = '82801H (ICH8 Family) SMBus Controller'
>>    class      = serial bus
>>    subclass   = SMBus
>> 
>> 
> 
> So, there's something broken in the initialization of the driver and the
> driver dependencies here.
> 
> If I load "smb.ko" by itself, no other modules are loaded (ichsmb,
> smbus).  Should it?

I don’t think so. If I kldload pci, would you expect most of the drivers in the system to be loaded?

> If I load ichsmb, smbus is loaded, so that's good.  But, the first time
> I do this, the driver seems to think I have 16 bus instances:
> 
> 
> iicsmb0: <SMBus over I2C bridge> on iicbus0
> iicsmb1: <SMBus over I2C bridge> on iicbus1
> iicsmb2: <SMBus over I2C bridge> on iicbus2
> iicsmb3: <SMBus over I2C bridge> on iicbus3
> iicsmb4: <SMBus over I2C bridge> on iicbus4
> iicsmb5: <SMBus over I2C bridge> on iicbus5
> iicsmb6: <SMBus over I2C bridge> on iicbus6
> iicsmb7: <SMBus over I2C bridge> on iicbus7
> iicsmb8: <SMBus over I2C bridge> on iicbus8
> iicsmb9: <SMBus over I2C bridge> on iicbus9
> iicsmb10: <SMBus over I2C bridge> on iicbus10
> iicsmb11: <SMBus over I2C bridge> on iicbus11
> iicsmb12: <SMBus over I2C bridge> on iicbus12
> iicsmb13: <SMBus over I2C bridge> on iicbus13
> iicsmb14: <SMBus over I2C bridge> on iicbus14
> iicsmb15: <SMBus over I2C bridge> on iicbus15
> smbus0: <System Management Bus> on iicsmb0
> smbus1: <System Management Bus> on iicsmb1
> smbus2: <System Management Bus> on iicsmb2
> smbus3: <System Management Bus> on iicsmb3
> smbus4: <System Management Bus> on iicsmb4
> smbus5: <System Management Bus> on iicsmb5
> smbus6: <System Management Bus> on iicsmb6
> smbus7: <System Management Bus> on iicsmb7
> smbus8: <System Management Bus> on iicsmb8
> smbus9: <System Management Bus> on iicsmb9
> smbus10: <System Management Bus> on iicsmb10
> smbus11: <System Management Bus> on iicsmb11
> smbus12: <System Management Bus> on iicsmb12
> smbus13: <System Management Bus> on iicsmb13
> smbus14: <System Management Bus> on iicsmb14
> smbus15: <System Management Bus> on iicsmb15
> 
> I then load smb.ko and I get no useful output from smbmsg -p.
> 
> If I try to acces /dev/smb1, ctrl-c it, unload all modules and then
> reload them, I get completely different (and functional) behavior.  I
> only get ONE smbus and I can poll "devices" there, even though I have no
> idea what they are.
> 
> ichsmb0: <Intel 82801H (ICH8) SMBus controller> port 0x1c60-0x1c7f mem
> 0xfe227400-0xfe2274ff irq 23 at device 31.3 on pci0
> smbus0: <System Management Bus> on ichsmb0
> smb0: <SMBus generic I/O> on smbus0
> root at bruno:/home/sbruno # smbmsg -p
> Probing for devices on /dev/smb0:
> Device @0x10: w
> Device @0x88: rw
> Device @0xa8: w
> Device @0xaa: rw
> Device @0xac: rw
> Device @0xae: rw
> Device @0xb8: rw
> Device @0xc2: w
> Device @0xc8: w
> 
> 
> 
> 
> 
> 
> Right ... so, I did the following:
> 
> kldload ichsmb
> 
> This seems to know to bull in smbus.ko.

I kinda think that’s a bug. Makes it impossible to load/unload smbus independent of ichsmb. pccard had that issue, but I fixed it eons ago. However, it might be a necessary at the moment bug due to symbols being exported from smbus.ko that are needed btt ichsmb…


> ichsmb0: <Intel 82801H (ICH8) SMBus controller> port 0x1c60-0x1c7f mem
> 0xfe227400-0xfe2274ff irq 23 at device 31.3 on pci0
> smbus0: <System Management Bus> on ichsmb0
> 
> 
> This doesn't really do anything useful, until I load "smb.ko”:

That makes sense to me. Again, each of these things is independent, or should be.

It sounds like there’s other breakage going on. You might want to see what putting it in your kernel tells you.

Warner