Arch Linux

valo

Member

From: IT

Registered: 2013-08-23

Posts: 8

Can't swapon on /dev/mtdblock0

Good morning everyone, I was trying to follow a mix of  [1] and [2] to be able to use my discrete gpu ram to extend my 4GB RAM given the fact I don't use it right now.  I managed to reach

#  lsblk
NAME             MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sda                8:0    0 465,8G  0 disk  
├─sda1             8:1    0 125,5M  0 part  /boot
└─sda2             8:2    0 465,7G  0 part  
  └─vg0          254:0    0 465,7G  0 crypt 
    ├─vg500-swap 254:1    0     4G  0 lvm   [SWAP]
    ├─vg500-root 254:2    0    30G  0 lvm   /
    └─vg500-home 254:3    0 431,6G  0 lvm   /home
sr0               11:0    1  1024M  0 rom   
mtdblock0         31:0    0   256M  0 disk  

But when I

#  swapon -fv /dev/mtdblock0
swapon /dev/mtdblock0
swapon: /dev/mtdblock0: read swap header failed

The other really strange thing is

lspci -vv
[....]
03:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Venus PRO [Radeon HD 8850M / R9 M265X] (rev ff) (prog-if ff)
        !!! Unknown header type 7f
        Kernel driver in use: radeon
        Kernel modules: radeon

Instead on linux mint debian edition everything works (lspci, phram, mtdblock, mkswap and swapon)

The ( I think) relevant part of dmesg

[1002:6823] type 00 class 0x030000
[  +0,000026] pci 0000:03:00.0: reg 0x10: [mem 0xd0000000-0xdfffffff 64bit pref]
[  +0,000018] pci 0000:03:00.0: reg 0x18: [mem 0xf0500000-0xf053ffff 64bit]
[  +0,000010] pci 0000:03:00.0: reg 0x20: [io  0x3000-0x30ff]
[  +0,000019] pci 0000:03:00.0: reg 0x30: [mem 0xfffe0000-0xffffffff pref]
[  +0,000090] pci 0000:03:00.0: supports D1 D2
[  +0,000003] pci 0000:03:00.0: PME# supported from D1 D2 D3hot

How can I proceed to understand what's going on?
Thanks

mich41

Member

Registered: 2012-06-22

Posts: 796

Re: Can't swapon on /dev/mtdblock0

Either the device is - for whatever reason - unreadable or it hasn't been initialized with mkswap.

Run head -c4k /dev/mtdblock0 |hexdump to see if it's readable.

Run mkswap /dev/mtdblock0 manually and see if it helps.

Last edited by mich41 (2014-11-22 17:06:04)

valo

Member

From: IT

Registered: 2013-08-23

Posts: 8

Re: Can't swapon on /dev/mtdblock0

Hi, thanks
So

 #  head -c4k /dev/mtdblock0 |hexdump
0000000 ffff ffff ffff ffff ffff ffff ffff ffff
*
0001000

I already tryed with

#  swapon -fv /dev/mtdblock0
swapon /dev/mtdblock0
swapon: /dev/mtdblock0: read swap header failed

And

#  mkswap /dev/mtdblock0
Setting up swapspace version 1, size = 262140 KiB
nessuna etichetta, UUID=9e28c521-abcd-44a9-a992-b7ad7668d347

#  swapon -v /dev/mtdblock0
swapon /dev/mtdblock0
swapon: /dev/mtdblock0: read swap header failed

It exits with 255 error code in both cases

Can the fact that it's a discrete card (with-of course-the open driver radeon) and it's dynamically switched off be a problem?
Thanks again

mich41

Member

Registered: 2012-06-22

Posts: 796

Re: Can't swapon on /dev/mtdblock0

Dunno. Did you try tweaking power saving options (see modinfo radeon)?