[maemo-users] Troubles with chrooted Debian

[From: Pavel Řezníček]

Dne 4.1.2012 22:34, Paul Hartman napsal(a):
> On Mon, Jan 2, 2012 at 6:19 PM, Pavel Řezníček<cigydd at gmail.com>  wrote:
>> OK, the SD-card may really be broken, that's right. I have to go for one and buy it (or via an e-shop) as soon as I have the time. Or, I may test this old one for bad blocks.
> Check your dmesg on N900, if you see some errors like this:
>
> [33713.501464] mmcblk1: error -110 sending read/write command,
> response 0x900, card status 0xe00
> [33713.501495] mmcblk1: error -110 transferring data, sector 27271168,
> nr 8, card status 0xc00
> [33713.570129] end_request: I/O error, dev mmcblk1, sector 27271169
> [33713.570159] Buffer I/O error on device mmcblk1p4, logical block 0
> [33713.570159] lost page write due to I/O error on mmcblk1p4
> [33754.895355] mmcblk1: error -110 transferring data, sector 30941184,
> nr 16, card status 0xc00
> [33754.895690] end_request: I/O error, dev mmcblk1, sector 30941185
> [33754.895721] Buffer I/O error on device mmcblk1p4, logical block 458752
> [33754.895751] lost page write due to I/O error on mmcblk1p4
> [33754.895812] end_request: I/O error, dev mmcblk1, sector 30941192
> [33754.895843] Buffer I/O error on device mmcblk1p4, logical block 458753
> [33754.895843] lost page write due to I/O error on mmcblk1p4
> [33755.504272] mmcblk1: error -110 transferring data, sector 31203328,
> nr 16, card status 0xc00
>
> means your card is incompatible with N900's MMC driver and you are
> most likely suffering data corruption. In my experience, class 6 and
> higher do not work properly in N900. Notice that other phones built on
> similar hardware have the same problem.
>
> But, good news, I made a fix to allow these cards to function without
> corruption. To apply this fix in your own kernel sources, edit
> drivers/mmc/host/omap_hsmmc.c replace the set_data_timeout function
> with this one:
>
> static void set_data_timeout(struct omap_hsmmc_host *host,
> unsigned int timeout_ns,
> unsigned int timeout_clks)
> {
> uint32_t reg;
>
> reg = OMAP_HSMMC_READ(host->base, SYSCTL);
>
> reg&= ~DTO_MASK;
> reg |= DTO<<  DTO_SHIFT;
> OMAP_HSMMC_WRITE(host->base, SYSCTL, reg);
> }
>
> The fix was included in latest power kernel 49, and in fact they
> included my fix in CyanogenMod since they have some Android phones
> based on same hardware as N900 such as Motorola Milestone, and they
> suffer the same SD card incompatibilities as N900. :)
>
> If you use the stock Nokia kernel and don't want to compile your own,
> let me know and I can provide a prebuilt module that you can replace
> on your phone. (at your own risk... if you do it wrong, you will
> probably create infinite reboot loop and have to flash. You have been
> warned! It works for me.)
>
> However, most of these fast cards have terrible small read/write I/O
> performance. They are great if you want to use it in a camera for
> saving single large file or video recording, but bad a computer
> filesystem.
>
> Sandisk is the king of fast small I/O. My class 2 sandisk 16GB card is
> about 10 times faster than class 10 A-Data card for small I/O. And of
> course the Sandisk work with no errors or corruption on unmodified
> N900, which is important. Plus, since Sandisk has a lower class
> rating, they are actually cheaper. :) I recently bought 32GB Sandisk
> class 4 for $30 USD from Amazon. Some of class 10 cards are $100.
>
> My personal collection of good and bad microSD cards on N900:
>
> Good (works on unmodded N900):
> Nokia 1GB that came with N900
> Sandisk 16GB class 2
> Sandisk 32GB class 4
>
> Bad (corruption on unmodded N900):
> Transcend 8GB class 6
> A-Data 16GB class 10
> A-Data 32GB class 6
> Lexar 32GB class 10
>
> Also be careful that many fake Sandisk and Kingston cards out there. I
> only buy mine from Amazon, sold by Amazon. Too many from other sellers
> and ebay, chinese sites, etc. are counterfeit. Lots of reports of
> "this card works" in talk.maemo.org and other forums, but just because
> the card is recognized and you can use it doesn't mean it works
> properly or is good performance... many people suffer random
> corruption or SD card goes read-only one day and they don't know this
> is the cause.
>
> Hope that helps!
> Paul

Dear Paul!

Your answer was so thorough and exhaustive that I can’t imagine a better 
one! Thank you very much for your time that you just invested in me and 
my N900 experience!

My current one and only card is TDK 8GB Life on Record, class unknown 
for now.

I’m not sure if I can buy one from Amazon directly because I’m neither 
an US nor UK resident.
Still thanks for your recommendation, it’s very valuable for me.

Compiling a kernel is a task which I’m a newbie in. I’ve played with it 
on two PCs running Mandriva but I don’t want to delve into it on my N900 
‘cause it was pretty annoying for me to set everything up again after a 
recent kernel upgrade (huh, didn’t know that the Nokia Suite is so 
stupid that it doesn’t conserve any settings in /home/user but just only 
the data in /home/user/MyDocs…). OK, I know now I could backup my 
personal settings pretty easily using rsync/grsync but don’t have the 
courage (and time) to play with the kernel at this moment… Maybe later.

I’d though appreciate if you send me the precompiled kernel module 
(along with some instructions or web resources how to install it).

Is it possible to wait until the new power kernel (49) is released and 
then install it in a standard manner from the repositories? Or is it 
already available to install?

Thank you again for your guidance.

Pavel

-- 
function Podpis(): String;
begin
   Jméno('Pavel Řezníček');
   Bydliště('Borová 18', '312 00', 'Plzeň');
   Pracoviště('Korandův sbor', 'Anglické nábřeží 13', '301 00', 'Plzeň');
   Result := 'vývojář a správce sítě';
end;

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