On 2 July 2012 16:47, Marc Dietrich <marvin24@xxxxxx> wrote: > Am Montag, 2. Juli 2012, 14:13:31 schrieb Saugata Das: >> On 2 July 2012 12:26, Venkatraman S <svenkatr@xxxxxx> wrote: >> > This reverts commit 3d93576e(skip card initialization if >> > power class selection fails). >> > Problem has been reported when this is used with eMMC4.41 >> > card with Tegra Platform. Till the issue is root caused, >> > bus width selection failure should not be treated as fatal. >> >> According to me, we need to find the root issue (which could be either >> host not able to provide enough current or faulty eMMC). Do we know, >> what could be the side effect of working on eMMC with less power than >> what it has requested in PWR_CL ? >> >> One known issue with the current power class selection is that we do >> not check the current requirement for a selected power class. It >> assumes that host is able to provide the maximum current needed at >> highest speed (> 800mA). Is it already checked on Tegra ? > > Acording to the schematic, the emmc is "fused" with 150mA and 450mA. There are > many supplies connected to it, so it is hard to tell what is the maximum, but > certainly not 800 mA. Why do you think it should be such high? Powerclass "7" > means 270 mA max and 160 mA RMS (dual voltage card). Btw, you may successfully > google for the "schematic document" for this "paz00" board in question. > I was referring to maximum current as per 4.5 spec (power class 15). I saw the logs which you sent earlier and the driver is trying to set power class 3 (=> 180mA RMS / 280mA peak). May be, you can check the regulators, if 450mA supply is enabled. > Marc > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
