Hi Jerome, On Thu, Apr 18, 2019 at 10:46 PM Jerome Brunet <jbru...@baylibre.com> wrote: > > On Thu, 2019-04-18 at 22:16 +0200, Martin Blumenstingl wrote: > > Hi Jerome, > > > > On Wed, Apr 17, 2019 at 10:44 PM Jerome Brunet <jbru...@baylibre.com> wrote: > > > Activating DDR in the Amlogic mmc controller, among other things, will > > > divide the output clock by 2. So by activating it with clock on, we are > > > creating a glitch on the output. > > > > > > Instead, let's deal with DDR when the clock output is off, when setting > > > the clock. > > > > > > Signed-off-by: Jerome Brunet <jbru...@baylibre.com> > > it seems that this patch breaks SD card on my Khadas VIM and Khadas VIM2. > > The error I see in your logs is with eMMC and hs200, not SD card. sorry, I should have been more clear that there are two errors: eMMC, this is what I have been seeing for a while on my Khadas VIM2 (it's probably not related to this patch): mmc1: mmc_select_hs200 failed, error -84 mmc1: error -84 whilst initialising MMC card
however, then there's this other error: print_req_error: I/O error, dev mmcblk0, sector 0 flags 0 Buffer I/O error on dev mmcblk0, logical block 0, async page read as result of this the partition table cannot be read and my kernel cannot find the rootfs. > Either way, There is something I don't really get. eMMC should not go through > any DDR mode to reach HS200 (which is an SDR mode), neither should SD to reach > HS. > > All this does is flipping the DDR bit (when necessary) when clock if off for > the mmc device, avoiding a glitch on clk line. > > This patch should not make any difference for SDR only setup, Maybe I missed > something, but I don't see how it could make anything different for SDR only. > > I (repeatedly) tested both vim1 and vim2, without seeing this issue, so I > can't > debug this. I'll need more detail to progress, something does not make sense > here. please let me know from which part of the driver do you want debug logs Regards Martin
