On Mi, 2018-10-10 at 17:15 -0700, Tony Lindgren wrote:
Hi,
interesting find. I thought self-refresh would mostly work automatic when there's no external clock to go into a power-saving mode - but it still depends on some timings.
Checking the datasheet of the RAM, there are five timings to be setup.
Two have min-values and three have max-values given, so no fixed timings... so there are some values we can test.
Additionally, there is a timing "tXSDLL" which seems to have something to do with the DLL. Description: "Exit Self Refresh to commands requiring a locked DLL"
So my guess is it sometimes hangs when it tries to exit self-refresh and we have DLL enabled?
Those timings are on page 52 of the RAM datasheet, in case you want to look for them.
And yes it's almost certain it's a self-refresh issue, if you disable it (change LP_MODE_SELF_REFRESH to LP_MODE_DISABLE in emif.h) the problem also goes away.
Yes I can confirm that too.
Regards,
Tony _______________________________________________ Kernel mailing list Kernel@pyra-handheld.com http://pyra-handheld.com/cgi-bin/mailman/listinfo/kernel