[Review] LeMaker Guitar

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Edited by MKT at Sun Nov 8, 2015 23:59

Hi !

Here is my LeMaker Guitar board review on hardware-libre.fr

Enjoy !
You inverted your link

Anyway, your article is interesting ... but I still wonder what is the goal of such SODIMM

Thanks for the testing

wonder if you can upload the testing video of Guitar.

I gonna share your report

Edited by hnsncxy at Mon Aug 17, 2015 05:51
However, there are a few bugs in this early release :

    I could not find how to change the display resolution, which is set on 1024*600 on a 1920*1080 display,
    my KVM switch doesn't work at all, but I expected this,
    the root partition is not expanded, so it is running out of free space very quickly. There’s 5.1Gb free in an unused partition.
    I think sound is not working (at least on HDMI)

Thanks for your review and feedback.
1.  We will provide the method which dynamic djust the resolution by the EDID in the standard system image
2. To support the KVM, may need to add some kernel configuration,and we will release Linux SDK in next month
3. Current ubuntu image use the GPT partitioned mode, and  you can use the parted command to use the unused space
4. The HDMI can output audio, and you can run "KODI" on the ubuntu, and use it to test the audio.

Edited by john.wen at Tue Aug 18, 2015 05:51

Maybe you can add a partition to expand the space as below:

1、Use parted to edit partitions
root@oftwl:~# parted /dev/mmcblk0                    
GNU Parted 2.3
Using /dev/mmcblk0
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print                                                            
Model: MMC H8G1e (sd/mmc)
Disk /dev/mmcblk0: 7818MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size    File system  Name      Flags
1      8389kB  58.7MB  50.3MB  fat16        MISC      msftdata
2      58.7MB  2743MB  2684MB  ext4         SYSTEM    msftdata
3      2743MB  2744MB  1049kB  fat32        BOOT_MSG  msftdata
4      2744MB  3013MB  268MB                SWAP      msftdata
5      3013MB  7810MB  4797MB  fat32        UDISK     msftdata


2、Delete the last 3 partitions
(parted) rm 5                                                             
udevadm settle is not permitted while udev is unconfigured.
udevadm settle is not permitted while udev is unconfigured.
(parted) rm 4                                                            
udevadm settle is not permitted while udev is unconfigured.
udevadm settle is not permitted while udev is unconfigured.
(parted) rm 3                                                            
udevadm settle is not permitted while udev is unconfigured.
udevadm settle is not permitted while udev is unconfigured.

3、Create a partition
(parted) mkpartfs
WARNING: you are attempting to use parted to operate on (mkpartfs) a file system.
parted's file system manipulation code is not as robust as what you'll find in
dedicated, file-system-specific packages like e2fsprogs.  We recommend
you use parted only to manipulate partition tables, whenever possible.
Support for performing most operations on most types of file systems
will be removed in an upcoming release.
Partition name?  []? EXTEND                                              
File system type?  [ext2]? ext2                                           
Start? 2743                                                               
End? -1                                                                  
writing per-group metadata... 97%       (time left 00:00)udevadm settle is not permitted while udev is unconfigured.
udevadm settle is not permitted while udev is unconfigured.

4、Mount the 3th partition to /mnt/
mount /dev/mmcblk0p3 /mnt/

Edited by tkaiser at Tue Aug 18, 2015 06:58

Since you can easily recreate the SD card's contents I would prefer a resize of the system partition while retaining a swap partition:

  • first uncomment the swap entry in /etc/fstab on /dev/mmcblk0p2
  • in parted change the units to sectors and let the partition table be printed out: "unit s" followed by "p"
  • then delete partitions 3-5
  • recreate the swap partition at the end of /dev/mmcblk0
  • do not a resize within parted but instead also delete partition 2 and recreate it starting at the very same sector as before until $start-of-swap -1
  • exit parted
  • let the resizefs command resize the ext4 partition
  • boot the card, check swap settings, adjust /etc/fstab accordingly and reboot again

(do a web search for "parted resize resizefs" to get the idea... or simply use GParted to resize interactively on the second system where you would run the above commands)

Regarding the swap partition: Since having swap on an SD card is always PITA and in this situation it really makes no difference whether it's a real swap partition or just an emergeny swap file an alternative approach would be to cancel creation of the swap partition and simply do something like this after resizing of partition/rootfs:

  • fallocate -l 256M /var/swap
  • mkswap /var/swap
  • swapon /var/swap

Don't forget to add "/var/swap none swap sw 0 0" to /etc/fstab afterwars (and comment the swap entry out before changing partitions)

Thanks for your answers. I'm not really comfortable with partitioning the NAND, especially since I don't have any backup or original image
If I understand well :
- john.wen solution creates a new 5.1Gb partition along the existing one. Problem is, root partition is so small it's impossible to install software or make updates. So this solution won't solve that.
- tkaiser solution expands the existing partition using the free one. This approach is what i'm looking for. But I see you're deleting partition 2 and then recreate it using the free space. If I delete partition 2, it will be empty when I recreate/expand it, right ? You then "boot the card". What does that mean ?

Edited by tkaiser at Tue Aug 18, 2015 09:50

Well, if LeMaker didn't supply you with an image you're able to burn on SD-card then my approach is too risky (I assumed you booted from TF card and can insert this into another Linux host to do the partitioning there). I wonder why LeMaker isn't able to provide an image for download that you can use as a boot source utilising a TF card... anyway I would then second john.wen's solution to expand the last partition.

But I would first check any swap entries in /etc/fstab (since deleting the swap partition might lead to errors on next reboot) and I would then transfer some stuff to the new partition and relink afterwards (try to identify a large portion of rather unused stuff using eg. du or better ncdu, then copy the stuff with rsync or tar and afterwards remove the source dir and replace it with a symlink to the new location -- that has to be defined in fstab as well!)

Have you tried to boot into single user mode (how to achieve that with the Guitar?), insert a TF card and simply block copy the NAND contents using dd to the TF card? And see what happens if you reboot with the TF card inserted? Does the Guitar support something like FEL mode we know from Allwinner SoCs? What's the procedure when your NAND gone bad? How to recover from such a situation?

And BTW: In your review there are a couple of (IMO obvious) questions unanswered:

  • what's the average consumption (you wrote about PSU requirements of 12V@2A -- this seems way too much to me)
  • which kernel version do they ship (uname -a) -- based on the infos I found on the web I would suspect it's an outdated kernel 3.10
  • can you put the output of dmesg and "lsusb -v" on pastebin.com?

Regarding the partition question: If you delete all partitions from the end of NAND to the beginning then you can also delete a partition containing a filesystem if you ensure that the freshly created new partition starts at the very same beginning (therefore I recommended to switch to sectors in parted using "unit s"). If LeMaker provides a guide how to backup NAND and be able to boot from a TF card I would go this route: deactivate swap, delete all partitions but the first and recreate the 2nd partition using "mkpart $former-value -1". Always ensure that you switched to sectors before. Then normally the rootfs will be unaffected unless you resize it using resizefs (the recommended method for ext3/ext4). Afterwards you could use the whole 8 GB for the rootfs minus the few MB for the first partition.

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