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Is Kernel module is the same as a device driver?

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Operating Systems Linux Fedora Is Kernel module is the same as a device driver?
# 15  
Old 05-06-2011
Corona688,

Thanks for the useful info. I'm researching my system' drivers now. It is interesting!
When I mentioned Windows, I had in mind a different chain Smilie. In Windows from device manager you can clearly identify all hardware and follow the chain to a driver, its resources etc. Apparently Windows uses a different design. The point is, that in windows it's all very visual, so it is easy to follow, even if its internal design is flowed. It is amazing how much I learned about system at this point!
# 16  
Old 05-06-2011
Quote:
Originally Posted by newlinuxuser1
When I mentioned Windows, I had in mind a different chain Smilie. In Windows from device manager you can clearly identify all hardware and follow the chain to a driver, its resources etc. Apparently Windows uses a different design. The point is, that in windows it's all very visual, so it is easy to follow, even if its internal design is flowed. It is amazing how much I learned about system at this point!
Whereas Linux is very file-oriented, and makes much of this information available via /sys and /proc instead.

Code:
# cat /proc/interrupts
           CPU0       CPU1       
  0:        145         69   IO-APIC-edge      timer
  1:        152      48712   IO-APIC-edge      i8042
  8:          0         51   IO-APIC-edge      rtc0
  9:        123      20212   IO-APIC-fasteoi   acpi
 12:       1521     503376   IO-APIC-edge      i8042
 16:       2247     262236   IO-APIC-fasteoi   ohci_hcd:usb3, ohci_hcd:usb4, hda_intel
 17:       5364     885282   IO-APIC-fasteoi   ehci_hcd:usb1, eth1
 18:        547     148897   IO-APIC-fasteoi   ohci_hcd:usb5, ohci_hcd:usb6, ohci_hcd:usb7, radeon@pci:0000:01:05.0
 19:          0         28   IO-APIC-fasteoi   ehci_hcd:usb2
 22:       1023     116912   IO-APIC-fasteoi   ahci
 27:          0          0   PCI-MSI-edge      eth0
NMI:          0          0   Non-maskable interrupts
LOC:   10791262   10628986   Local timer interrupts
SPU:          0          0   Spurious interrupts
PMI:          0          0   Performance monitoring interrupts
PND:          0          0   Performance pending work
RES:    2676499    2454427   Rescheduling interrupts
CAL:        153        128   Function call interrupts
TLB:       2406      13489   TLB shootdowns
THR:          0          0   Threshold APIC interrupts
MCE:          0          0   Machine check exceptions
MCP:         69         69   Machine check polls
ERR:          0
MIS:          0
# cat /proc/cpuinfo
processor	: 0
vendor_id	: AuthenticAMD
cpu family	: 17
model		: 3
model name	: AMD Turion(tm) X2 Ultra Dual-Core Mobile ZM-82
stepping	: 1
cpu MHz		: 550.000
cache size	: 1024 KB
physical id	: 0
siblings	: 2
core id		: 0
cpu cores	: 2
apicid		: 0
initial apicid	: 0
fpu		: yes
fpu_exception	: yes
cpuid level	: 1
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow constant_tsc rep_good nonstop_tsc extd_apicid pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy 3dnowprefetch osvw skinit lbrv svm_lock nrip_save
bogomips	: 4398.51
TLB size	: 1024 4K pages
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: ts ttp tm stc 100mhzsteps hwpstate

processor	: 1
vendor_id	: AuthenticAMD
cpu family	: 17
model		: 3
model name	: AMD Turion(tm) X2 Ultra Dual-Core Mobile ZM-82
stepping	: 1
cpu MHz		: 550.000
cache size	: 1024 KB
physical id	: 0
siblings	: 2
core id		: 1
cpu cores	: 2
apicid		: 1
initial apicid	: 1
fpu		: yes
fpu_exception	: yes
cpuid level	: 1
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow constant_tsc rep_good nonstop_tsc extd_apicid pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy 3dnowprefetch osvw skinit lbrv svm_lock nrip_save
bogomips	: 4398.70
TLB size	: 1024 4K pages
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: ts ttp tm stc 100mhzsteps hwpstate
# cat /proc/ioports
0000-0cf7 : PCI Bus 0000:00
  0000-001f : dma1
  0020-0021 : pic1
  0040-0043 : timer0
  0050-0053 : timer1
  0060-0060 : keyboard
  0064-0064 : keyboard
  0070-0071 : rtc0
  0080-008f : dma page reg
  00a0-00a1 : pic2
  00c0-00df : dma2
  00f0-00ff : fpu
  0170-0177 : 0000:00:14.1
  01f0-01f7 : 0000:00:14.1
  0376-0376 : 0000:00:14.1
  03c0-03df : vga+
  03f6-03f6 : 0000:00:14.1
  0400-04cf : pnp 00:09
    0400-0403 : ACPI PM1a_EVT_BLK
    0404-0405 : ACPI PM1a_CNT_BLK
    0408-040b : ACPI PM_TMR
    0410-0415 : ACPI CPU throttle
    0420-0427 : ACPI GPE0_BLK
  04d0-04d1 : pnp 00:09
  04d6-04d6 : pnp 00:09
  0680-06ff : pnp 00:09
  077a-077a : pnp 00:09
  0800-0800 : ACPI PM2_CNT_BLK
  0c00-0c01 : pnp 00:09
  0c14-0c14 : pnp 00:09
  0c50-0c52 : pnp 00:09
  0c6c-0c6c : pnp 00:09
  0c6f-0c6f : pnp 00:09
  0cd0-0cdb : pnp 00:09
0cf8-0cff : PCI conf1
0d00-ffff : PCI Bus 0000:00
  1000-1fff : PCI Bus 0000:80
  2000-2fff : PCI Bus 0000:09
    2000-20ff : 0000:09:00.0
      2000-20ff : r8169
  3000-4fff : PCI Bus 0000:02
  5000-5fff : PCI Bus 0000:01
    5000-50ff : 0000:01:05.0
  6000-600f : 0000:00:14.1
  6010-601f : 0000:00:11.0
    6010-601f : ahci
  6030-6037 : 0000:00:11.0
    6030-6037 : ahci
  6038-603f : 0000:00:11.0
    6038-603f : ahci
  6048-604b : 0000:00:11.0
    6048-604b : ahci
  604c-604f : 0000:00:11.0
    604c-604f : ahci
# dmesg | less
[    0.000000] Initializing cgroup subsys cpuset
[    0.000000] Initializing cgroup subsys cpu
[    0.000000] Linux version 2.6.34-gentoo-r6 (root@TheFuriousWeird) (gcc versio
n 4.4.3 (Gentoo 4.4.3-r2 p1.2) ) #3 SMP Thu Sep 23 08:23:15 CST 2010
[    0.000000] Command line: root=/dev/sda5
[    0.000000] BIOS-provided physical RAM map:
[    0.000000]  BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
[    0.000000]  BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
[    0.000000]  BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
[    0.000000]  BIOS-e820: 0000000000100000 - 00000000afb8f000 (usable)
[    0.000000]  BIOS-e820: 00000000afb8f000 - 00000000afc3c000 (ACPI NVS)
[    0.000000]  BIOS-e820: 00000000afc3c000 - 00000000afd70000 (usable)
[    0.000000]  BIOS-e820: 00000000afd70000 - 00000000afdbf000 (reserved)
[    0.000000]  BIOS-e820: 00000000afdbf000 - 00000000afe58000 (usable)
[    0.000000]  BIOS-e820: 00000000afe58000 - 00000000afebf000 (ACPI NVS)
[    0.000000]  BIOS-e820: 00000000afebf000 - 00000000afeee000 (usable)
[    0.000000]  BIOS-e820: 00000000afeee000 - 00000000afeff000 (ACPI data)
[    0.000000]  BIOS-e820: 00000000afeff000 - 00000000aff00000 (usable)
[    0.000000]  BIOS-e820: 00000000e0000000 - 00000000e4000000 (reserved)
[    0.000000]  BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved)
[    0.000000]  BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
[    0.000000]  BIOS-e820: 00000000fff00000 - 0000000100000000 (reserved)
[    0.000000]  BIOS-e820: 0000000100000000 - 0000000140000000 (usable)
[    0.000000] NX (Execute Disable) protection: active
[    0.000000] DMI 2.4 present.
[    0.000000] e820 update range: 0000000000000000 - 0000000000001000 (usable) ==> (reserved)
[    0.000000] e820 remove range: 00000000000a0000 - 0000000000100000 (usable)
[    0.000000] No AGP bridge found
[    0.000000] last_pfn = 0x140000 max_arch_pfn = 0x400000000
[    0.000000] MTRR default type: uncachable
[    0.000000] MTRR fixed ranges enabled:
[    0.000000]   00000-9FFFF write-back
[    0.000000]   A0000-FFFFF uncachable
[    0.000000] MTRR variable ranges enabled:
[    0.000000]   0 base 00FFF00000 mask FFFFF00000 write-protect
[    0.000000]   1 base 0000000000 mask FF80000000 write-back
[    0.000000]   2 base 0080000000 mask FFE0000000 write-back
[    0.000000]   3 base 00A0000000 mask FFF0000000 write-back
[    0.000000]   4 base 0100000000 mask FFC0000000 write-back
[    0.000000]   5 disabled
[    0.000000]   6 disabled
[    0.000000]   7 disabled
[    0.000000] TOM2: 0000000140000000 aka 5120M
[    0.000000] x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106
[    0.000000] last_pfn = 0xaff00 max_arch_pfn = 0x400000000
[    0.000000] e820 update range: 0000000000001000 - 0000000000010000 (usable) ==> (reserved)
[    0.000000] Scanning 1 areas for low memory corruption
[    0.000000] modified physical RAM map:
[    0.000000]  modified: 0000000000000000 - 0000000000010000 (reserved)
[    0.000000]  modified: 0000000000010000 - 000000000009fc00 (usable)
[    0.000000]  modified: 000000000009fc00 - 00000000000a0000 (reserved)
[    0.000000]  modified: 00000000000e0000 - 0000000000100000 (reserved)
[    0.000000]  modified: 0000000000100000 - 00000000afb8f000 (usable)
[    0.000000]  modified: 00000000afb8f000 - 00000000afc3c000 (ACPI NVS)
[    0.000000]  modified: 00000000afc3c000 - 00000000afd70000 (usable)
[    0.000000]  modified: 00000000afd70000 - 00000000afdbf000 (reserved)
[    0.000000]  modified: 00000000afdbf000 - 00000000afe58000 (usable)
[    0.000000]  modified: 00000000afe58000 - 00000000afebf000 (ACPI NVS)
[    0.000000]  modified: 00000000afebf000 - 00000000afeee000 (usable)
[    0.000000]  modified: 00000000afeee000 - 00000000afeff000 (ACPI data)
[    0.000000]  modified: 00000000afeff000 - 00000000aff00000 (usable)
[    0.000000]  modified: 00000000e0000000 - 00000000e4000000 (reserved)
[    0.000000]  modified: 00000000fec00000 - 00000000fec01000 (reserved)
[    0.000000]  modified: 00000000fee00000 - 00000000fee01000 (reserved)
[    0.000000]  modified: 00000000fff00000 - 0000000100000000 (reserved)
[    0.000000]  modified: 0000000100000000 - 0000000140000000 (usable)
[    0.000000] initial memory mapped : 0 - 20000000
[    0.000000] init_memory_mapping: 0000000000000000-00000000aff00000
[    0.000000]  0000000000 - 00afe00000 page 2M
[    0.000000]  00afe00000 - 00aff00000 page 4k
[    0.000000] kernel direct mapping tables up to aff00000 @ 16000-1b000
[    0.000000] init_memory_mapping: 0000000100000000-0000000140000000
[    0.000000]  0100000000 - 0140000000 page 2M
[    0.000000] kernel direct mapping tables up to 140000000 @ 19000-1f000
[    0.000000] ACPI: RSDP 00000000000fe020 00024 (v02 HP    )
[    0.000000] ACPI: XSDT 00000000afefe120 0005C (v01 HPQOEM SLIC-MPC 00000003      01000013)
[    0.000000] ACPI: FACP 00000000afefd000 000F4 (v04 HP     3045     00000003 MSFT 0100000D)
[    0.000000] ACPI: DSDT 00000000afef1000 0850E (v01 HP     3045     F0000000 INTL 20051117)
[    0.000000] ACPI: FACS 00000000afe61000 00040
[    0.000000] ACPI: HPET 00000000afefc000 00038 (v01 HP     3045     00000001 MSFT 000F4240)
[    0.000000] ACPI: APIC 00000000afefb000 00084 (v02 HP     3045     00000001 TFSM 000F4240)
[    0.000000] ACPI: MCFG 00000000afefa000 0003C (v01 HP     3045     00000001 TFSM 000F4240)
[    0.000000] ACPI: BOOT 00000000afef0000 00028 (v01 HP     3045     00000001    ? 00000001)
[    0.000000] ACPI: SLIC 00000000afeef000 00176 (v01 HPQOEM SLIC-MPC 06040000  LTP 00000001)
[    0.000000] ACPI: SSDT 00000000afeee000 00386 (v01 AMD    PowerNow 00000001 AMD  00000001)
[    0.000000] ACPI: Local APIC address 0xfee00000
[    0.000000] Scanning NUMA topology in Northbridge 24
[    0.000000] No NUMA configuration found
[    0.000000] Faking a node at 0000000000000000-0000000140000000
[    0.000000] Initmem setup node 0 0000000000000000-0000000140000000
[    0.000000]   NODE_DATA [0000000100000000 - 0000000100004fff]
[    0.000000]  [ffffea0000000000-ffffea00045fffff] PMD -> [ffff880100200000-ffff8801037fffff] on node 0
[    0.000000] Zone PFN ranges:
[    0.000000]   DMA      0x00000010 -> 0x00001000
[    0.000000]   DMA32    0x00001000 -> 0x00100000
[    0.000000]   Normal   0x00100000 -> 0x00140000
[    0.000000] Movable zone start PFN for each node
[    0.000000] early_node_map[7] active PFN ranges
[    0.000000]     0: 0x00000010 -> 0x0000009f
[    0.000000]     0: 0x00000100 -> 0x000afb8f
[    0.000000]     0: 0x000afc3c -> 0x000afd70
[    0.000000]     0: 0x000afdbf -> 0x000afe58
[    0.000000]     0: 0x000afebf -> 0x000afeee
...
(on and on for 1000+ lines)

---------- Post updated at 08:13 PM ---------- Previous update was at 08:12 PM ----------

The contents of /sys/ are so low-level I don't understand much of them but you can find quite a lot in there, apparently.
# 17  
Old 05-10-2011
Corona688,

thank you for the post. I spent three days learning about the commands and info they pull out. I'm still on it. Thank man!
# 18  
Old 05-12-2011
BTW, is there a database or repository to check on existing drivers before buying a device? My understanding that in most cases Linux drivers aren't provided by manufacturers but mostly by a community. I found numerous discussion forums for Ubuntu and some HCLs.
And, is there an issue of using old drivers with newer versions of kernel, or they are compatible? It's my understanding that 64-bit and 32-bit require different drivers.
Are Linux drivers universal and fit into all Linux flavors or let say Fedora needs one driver and Debian another?
# 19  
Old 05-12-2011
Quote:
Originally Posted by newlinuxuser1
BTW, is there a database or repository to check on existing drivers before buying a device?
The closest thing Linux has to a central repository is the kernel source itself(and the information provided by make menuconfig). But it's usually chipset-oriented, not device-oriented -- it will tell you the driver supports Realtek xxxxxx, not that it supports So-And-So Generic Brand Name Network Card. So I usually just google it, and that tells me what module to use if any, and from there I can find info in the kernel configuration utility.
Quote:
My understanding that in most cases Linux drivers aren't provided by manufacturers but mostly by a community.
Correct. The same community that maintains the Linux kernel I think, since almost all of Linux's open device drivers are bundled with the kernel source code.
Quote:
And, is there an issue of using old drivers with newer versions of kernel
When you update your kernel, you update your drivers too, for they come with it. (third-party drivers excepted.) You can have drivers for several different kernels installed and they won't overlap because the kernel knows what version it is and loads from different directories (/lib/modules/kernel-version/...) This is where third-party drivers go too, so when you update your kernel, if you didn't reinstall the third-party driver, the new kernel simply won't find it.

Binary drivers from third parties usually need to be updated for new kernel versions. They often come in two parts, a binary part that changes less often, and a small stub of source code to tie it to the kernel. It's this stub that gets compiled to turn the binary into a driver Linux can load.

Even then, sometimes a newer kernel means you need a newer binary too. A newer kernel can mean architecture changes inside the kernel which they have to re-engineer something to fit.
Quote:
It's my understanding that 64-bit and 32-bit require different drivers.
Yes, they are very different. Broadcom for instance has two versions of its proprietary driver, one for 32-bit and one for 64-bit Linux systems. A 64-bit kernel can run 64-bit and 32-bit programs, but a 32-bit kernel can only run 32-bit programs.

Other architectures need their own drivers too. SPARC and PPC and ARM all need their own drivers. Even if it's the same device driver being compiled, the executable code naturally ends up being very different.
Quote:
Are Linux drivers universal and fit into all Linux flavors or let say Fedora needs one driver and Debian another?
That depends. The Linux kernel is extremely configurable, and radically different configurations of the kernel may not work with drivers meant for a different configuration. If at all possible you'd want a device driver built inside, or at least using the same source code and configuration used to build your kernel.
This User Gave Thanks to Corona688 For This Post:
newlinuxuser1
# 20  
Old 05-14-2011
Corona688, thank you man! My head is spinning at his point. I feel like five years old taken to a planetarium. They show you the planets on a fake night sky and it appears nice and easy, feel exciting... until you start asking them questions... they tell you that you really get it only after years of dedicated learning Smilie
I'm taking a wine break today Smilie
# 21  
Old 05-17-2011
Corona688,
I was thinking about what you said, about kernel update. Do you update kernel outside of Linux release you use? I mean there was Fedora 12, then 13, now it's 14. Do you upgrade kernel between releases?
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