Hi Simon, On Mon, Aug 14, 2017 at 07:10:23AM +0200, Simon Horman wrote: > On Tue, Aug 08, 2017 at 08:54:45PM +0200, Wolfram Sang wrote: > > > > > As it is an "RFT" I'm happy to apply it if you repost > > > it or otherwise indicate that is what you would like to happen. > > > > As discussed in a chat, I tried SDR104 with my SDIO WiFi cards: > > > > H3: > > - one slot worked flawlessly > > - one slot could load FW but failed to read status > > (with SDR50: both slots work) > > > > M3-W: > > - both slots could not load the firmware > > (with SDR50: one slot works, one fails to load FW) > > > > The cards, however, were correctly identified as SDR104 and there were > > no tuning errors and no other SDHI related warnings. > > > > Changing TDSEL in the PFC did not change anything. > > > > The manual of the WiFi card (u-blox EMMY-W1) mentions a maximum line > > length of 100mm. Measuring a direct line from the SoC to the slots, > > I'd think we are very much on the edge of that. And given the length > > of the SDIO adapter, we are surely exceeding that :( > > > > Maybe we should do more tests with more boards? On the other hand, it > > seems the WiFi card is running out of the specs. > > > > So much for now. I'll sleep over it and try to get more data tomorrow. > > Thanks. Unfortunately my H3 is out of arms length but I can arrange > some testing if it is helpful. Do you have UHS-SDIO cards? Otherwise, some more testing in Spain will be good. > Is one possibility to enable it for the slots listed above that are now > thought to work but not for the other one? I don't think so. We'd need more test coverage. My gut feeling is that it varies from board to board. Or more precisely: from environment around the board to environment around the board. I'd like to test a) more boards) and b) a resoldered WLAN card to skip the extra cabling there. I still think the wire length of ~23cm (exceeding the spec of max 10cm) is a factor here, so resoldering would save ~6cm. That all sounds to me like a hacking sprint for our next meeting. Maybe ULCB has less line lengths? Would be interesting to check, too. I could also try to apply more shielding here at home, too. > The SDR50 failure on M3-W seems particularly troubling as that > has been enabled in upstream for a while, right? Not nice, yes. Yet, until this thread, there have been no issues reported. So, it doesn't look like a substantial fault to me (famous last words?) Regards, Wolfram
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