2 mods with same PCI-ID table, one installs, other fails modprobe

[Jim Cromie]

(aside - whats the correct ML?  Ive used both suggested by my mail interface)

I have 2 modules with same modinfo alias,
one installs, the other gets -ENODEV.
Id expect them to both act the same.
What am I missing ?

root at voyage:~# modprobe geode-aes
root at voyage:~# lsmod |grep geode_aes
geode_aes               4229  0

root at voyage:~# modprobe geode-rng
dynamic_debug:ddebug_remove_module: removing module "geode_rng"
FATAL: Error inserting geode_rng
(/lib/modules/3.0.0-skc-dyndbg+/kernel/drivers/char/hw_random/geode-rng.ko):
No such device

root at voyage:~# modinfo geode-aes
filename:
/lib/modules/3.0.0-skc-dyndbg+/kernel/drivers/crypto/geode-aes.ko
license:        GPL
description:    Geode LX Hardware AES driver
author:         Advanced Micro Devices, Inc.
alias:          pci:v00001022d00002082sv*sd*bc*sc*i*
depends:
vermagic:       3.0.0-skc-dyndbg+ preempt mod_unload modversions GEODEGX1

root at voyage:~# modinfo geode-rng
filename:
/lib/modules/3.0.0-skc-dyndbg+/kernel/drivers/char/hw_random/geode-rng.ko
license:        GPL
description:    H/W RNG driver for AMD Geode LX CPUs
alias:          pci:v00001022d00002082sv*sd*bc*sc*i*
depends:        rng-core
vermagic:       3.0.0-skc-dyndbg+ preempt mod_unload modversions GEODEGX1

IE both have same alias, and (unsurprisingly) the same DEVICE_ID.

geode-rng's 1 dependency isnt the problem:
root at voyage:~# modprobe rng-core
root at voyage:~# lsmod |grep rng
rng_core                3010  0


DEVICE-IDs:

jimc at chumly:~/projects/lx/linux-2.6/drivers/crypto$ grep PCI_DEV geode-aes.c
	{ PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_LX_AES), } ,
jimc at chumly:~/projects/lx/linux-2.6/drivers/crypto$ cd ../char/hw_random/
jimc at chumly:~/projects/lx/linux-2.6/drivers/char/hw_random$ grep
PCI_DEV geode-rng.c
	{ PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_LX_AES), 0, },

hmmm.  is that trailing 0 important ?
Id think not, {..} is a literal constant assignment, 0 is only sensible default.

The apparent diff is how the __init is done.

static struct pci_device_id geode_aes_tbl[] = {
	{ PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_LX_AES), } ,
	{ 0, }
};

MODULE_DEVICE_TABLE(pci, geode_aes_tbl);

static struct pci_driver geode_aes_driver = {
	.name = "Geode LX AES",
	.id_table = geode_aes_tbl,
	.probe = geode_aes_probe,
	.remove = __devexit_p(geode_aes_remove)
};

static int __init
geode_aes_init(void)
{
	return pci_register_driver(&geode_aes_driver);
}



geode-rng does it the (older?) more manual way:


static int __init mod_init(void)
{
	int err = -ENODEV;
	struct pci_dev *pdev = NULL;
	const struct pci_device_id *ent;
	void __iomem *mem;
	unsigned long rng_base;

	for_each_pci_dev(pdev) {
		ent = pci_match_id(pci_tbl, pdev);
		if (ent)
			goto found;
	}
	/* Device not found. */
	goto out;

found:
...



Qs
1 - why do they differ in modprobe results ?
bug likely ??

2 - which is correct ? success or failure ?

FWIW, heres my PCI devices.
The CPU is an SC1100 - its a Geode, but not a Geode-GX or LX
(though the distinctions arent as clear as Id like :-/)

root at voyage:~# lspci -nn
00:00.0 Host bridge [0600]: Cyrix Corporation PCI Master [1078:0001]
00:06.0 Ethernet controller [0200]: National Semiconductor Corporation
DP83815 (MacPhyter) Ethernet Controller [100b:0020]
00:07.0 Ethernet controller [0200]: National Semiconductor Corporation
DP83815 (MacPhyter) Ethernet Controller [100b:0020]
00:08.0 Ethernet controller [0200]: National Semiconductor Corporation
DP83815 (MacPhyter) Ethernet Controller [100b:0020]
00:0a.0 Ethernet controller [0200]: Belkin Wireless PCI Card - F5D6001
[1799:6001] (rev 20)
00:0e.0 Ethernet controller [0200]: Marvell Technology Group Ltd.
88W8361 [TopDog] 802.11n Wireless [11ab:2a02] (rev 03)
00:12.0 ISA bridge [0601]: National Semiconductor Corporation SC1100
Bridge [100b:0510]
00:12.1 Bridge [0680]: National Semiconductor Corporation SC1100 SMI &
ACPI [100b:0511]
00:12.2 IDE interface [0101]: National Semiconductor Corporation
SCx200, SC1100 IDE controller [100b:0502] (rev 01)
00:12.5 Bridge [0680]: National Semiconductor Corporation SC1100 XBus
[100b:0515]
00:13.0 USB Controller [0c03]: Compaq Computer Corporation ZFMicro
Chipset USB [0e11:a0f8] (rev 08)

Specifically, theres no AMD ID in the output

root at voyage:~# lspci -nn |grep 1022
root at voyage:~# lspci -nn |grep 100b
00:06.0 Ethernet controller [0200]: National Semiconductor Corporation
DP83815 (MacPhyter) Ethernet Controller [100b:0020]


>From all this, it seems that the failure to install is correct,
which suggests some bug in pci_register_driver,
but its hard to imagine that - otherwize its survived (well hidden)
for a long time