[maemo-developers] Firmware 4.2007.26-8 has inferior SDHC performance than 3.2007.10-7 - why?

[From: Frantisek Dufka]

Here are relevant parts of kernel changelog

kernel-source-rx-34 (2.6.18-osso42) unstable; urgency=low 
 

 
 

   * week200713-1 release 
 

   * MMC: Add support for mmc v4 high speed mode 
 

   * mmc: Support for high speed SD cards 
 

   * mmc: Add support for SDHC cards 
 

   * mmc: Graceful fallback for fancy features 
 

   * mmc: MMC sector based cards 
 

 
 

  -- Yauheni Kaliuta <yauheni.kaliuta at nokia.com>  Tue, 27 Mar 2007 
15:15:01 +0300 


...

kernel-source-rx-34 (2.6.18-osso47) unstable; urgency=low 
 

 
 

   * week200721-1 release 
 

   * MMC: Limit the mmc clock to 24MHz. Fixes: NB#54313 
 

 
 

  -- Yauheni Kaliuta <yauheni.kaliuta at nokia.com>  Mon, 21 May 2007 
16:33:49 +0300


It may be that MMC speed is limited to 24Mhz (wonder what NB#54313 is 
about) for similar reason like N770 MMC speed being limited to 12Mhz - 
better compatibility by sacrificing speed. Sadly this makes perfect 
sense for Nokia.

While this was real pain with N770 (approx 1.4MB/s read speed, 300KB/s 
write speed) with N800 it is not that bad. After all 7 or 11MB/s is not 
such big difference in real life. I'm far more concerned about device 
physically corrupting cards (like someone reported in ITT forum and 
bugzilla).

Frantisek