Enable SSD support in kernel for T100TA

[cheatman]

Hey guys,

I have searched for this and have not found any similar posts.

I am building the 3.18 kernel (not modified) and it does not include SSD support at all. The images posted based on this kernel detect my SSD, but the one I build does not. I would have expected the GIT repo to contain the code that results in the image posted (which works with SSD just fine), including the appropriate kernel config.

Just so that I am clear enough: grub loads fine, boots and loads the kernel from the SSD, the kernel starts fine, no errors, but does not list the SSD (nornally /dev/block/mmcblk0), only the HDD (/dev/block/sda) as drives.

Questions:

1. Do I need to enable SSD support in the defconfig for my target?

2. If so, which modules are required for Asus T100 hardware?

3. Do I need to compile using any other special considerations?

Cheers,

C.

[Chih-Wei Huang]

2015/1/6 上午3:35 於 "cheatman" <ciprian...@gmail.com> 寫道：
>
> Hey guys,
>
> I have searched for this and have not found any similar posts.
>
> I am building the 3.18 kernel (not modified) and it does not include SSD support at all. The images posted based on this kernel detect my SSD, but the one I build does not. I would have expected the GIT repo to contain the code that results in the image posted (which works with SSD just fine), including the appropriate kernel config.

Which image and git repo did you refer to?
The 4.4-r2 release uses exact the kernel and config
from android-3.18 branch of git.android-x86.org?

> Just so that I am clear enough: grub loads fine, boots and loads the kernel from the SSD, the kernel starts fine, no errors, but does not list the SSD (nornally /dev/block/mmcblk0), only the HDD (/dev/block/sda) as drives.
>
> Questions:
>
> 1. Do I need to enable SSD support in the defconfig for my target?
> 2. If so, which modules are required for Asus T100 hardware?
> 3. Do I need to compile using any other special considerations?

If I remember correctly, the drivers needed for SSD are
sdhci and sdhci-acpi.
Both are enabled in the android-x86_defconfig
of android-3.18 branch.
No additional patch or config is needed.

Did you build the android-3.18 branch from git.android-x86.org?

[cheatman]

I synced the lollipop branch and made no changes to the code. Then, I compiled the kernel only. The resulting bzImage kernel has the modules you mentioned in the defconfig file.

A similar configuration for the kernel for Ubuntu works fine (detects mmc0).

I will double and triple check again today and try the 3.19 kernel updated by pstglia as well.

If you have any further ideas or want additional info, let me know.

Cheers,
C.

[Fajar A. Nugraha]

On Tue, Jan 6, 2015 at 1:39 PM, cheatman <ciprian...@gmail.com> wrote:
> I synced the lollipop branch and made no changes to the code. Then, I compiled the kernel only. The resulting bzImage kernel has the modules you mentioned in the defconfig file.
>
> A similar configuration for the kernel for Ubuntu works fine (detects mmc0).
>
> I will double and triple check again today and try the 3.19 kernel updated by pstglia as well.

FYI, 3.19 would still have erros on T100, even if you manage to get it loaded
https://plus.google.com/115582184723609367547/posts/DHi1ERxEV9c

I'm also curious why (when using the released ISOs), the SD card is
detected as mmcblk0, but the SD card isn't (it's normally detected as
mmcblk1 under linux) when both should be using the same kernel module.

--
Fajar

[cheatman]

Fajar,

The commits may not solve all the issues, but they are a great step in the right direction.

Even so, we need the commits anyway, once a fully working solution is found so this work is not wasted. Using the latest patches, things are a lot better on Ubuntu. Let's see if they improve Android as well.

Cheers,
C.

[cheatman]

There was a problem with the defconfig after all. I used the one in pstglia's kernel and it compiles with SSD support. I have not tracked down the issue specifically (although I can easily do a diff on the two files) so I have no real idea what the problem was.

The x86_64 defconfig builds fine with emmc/ssd support as well.

Anyway, the build completed fine and I was able to test the commits and they work. Not completely (the disk I/O still goes out of sync), but it takes more operations to reach this stage. So, unless we write over 5GB of data to the tablet drive in one session, it should work fine.

Cheers and thanks to Chih-Wei Huang and pstglia for their help on this! Once a stable 3.19 will be out, the T100 will probably get better support and become more usable.

C.