#qi-hardware IRC log for Wednesday, 2014-07-16

wpwrakwhitequark: the google translation is hilarious :) "web malfunction, power surges, broken arrow."03:33
wpwrakthe list seems to include pretty much all possibilities03:34
kyakbecause at the moment pretty much all of them are possible03:47
kyakso any discussion is merely a specilation now03:48
wpwrakhmm, seems we lost the mount point again :-( no file son downloads ...10:02
apeleteHi larsc19:58
apeletelarsc: got some time ? I have a log sequence I'ml trying to make sense of20:06
larscmake it quick ;)20:07
apeleteI wrote mmc async request pre_req() and post_req() callbacks to speed up dma transfers20:07
apeletebut it fails: http://paste.debian.net/109993/20:08
apeletelarsc: seems like CMD13 is timing out at the end of the boot sequence20:08
apeleteand I'm trying to figure out why20:09
apeleteerror 145 is returned by get_card_status() in drivers/mmc/card/block.c:90920:11
apeletethat is in mmc_blk_cmd_recovery(): http://lxr.free-electrons.com/source/drivers/mmc/card/block.c#L90920:12
apeletelarsc: how is CMD13 supposed to be handled by host driver (jz4740_mmc.c) ?20:13
apeletebeen reading the datasheet but didn't see anything wrong with the way it's being handled now20:15
larscapelete: probably unrelated, but the way you allocate and submit the descriptor is not safe20:15
larscyou must submit the descriptor immediately after you allocated it20:16
larscso that should not be done in pre_request20:16
larsconly the mapping of the dma area can be done there20:17
apeletelarsc: so only dma_map_sg() shoukd be done in pre_request ?20:17
apeletethat was my very first implementation, it worked but I didn't notice any speed improvement20:18
apeleteso I moved desc allocation to pre_request too, hoping it would speed things up further20:19
larscdmaengine_prep_slave_sg() is very light20:19
larscshould make a difference performance wise20:19
apeletelarsc: ok, I'm going to revert back to my first try and only do dma_map_sg in pre_request20:20
apeletelarsc: thanks for your time :)20:21
pcercueiwhat saves most power for an unused pin? Set as input, output with pullup low, pullup high?23:33
wpwrak"unused" = unconnected ? i'd measure :) in general, output or pull is best. some chips also have an "unused" configuration which can be better. "input" is bad because you may pick up interferences, causing the input to switch violently and burning energy23:36
pcercueiok, that's good to know23:36
pcercueinot unconnected, just unused23:36
wpwrakthen the best configuration would depend on what it is connected to :)23:37
wpwrakhmm, downloads.qi-hardware.com still has no files :-(23:52
wpwrakand in found some dumb mistakes in the new anelok layout. well, so far nothing catastrophic23:53
--- Thu Jul 17 201400:00

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