> From: Gerd Hoffmann [mailto:kra...@redhat.com] > Sent: Friday, 22 April 2016 09:46 > > Alternatively we can just go for a later boot loader stage, i.e. put a u-boot > build > for rpi2 to pc-bios/ (we already have one for ppc there) and run that by > default. > > Our sdcard emulation seems to have problems though: > > U-Boot 2016.05-rc2 (Apr 22 2016 - 09:11:45 +0200) > > DRAM: 960 MiB > RPI 2 Model B (0xa21041) > MMC: <uboot hangs here> > > Recent linux kernels have trouble talking to the mmc too.
I know :( I haven't looked at the more recent kernels, but it could be the same issue I spent a while debugging fruitlessly on raspi1 -- it looked like Linux was issuing a large MMC read for N blocks, but only programming the DMA controller for fewer (<N*blocksize). The DMA reads completed quickly but eventually the kernel timed out, logged an error and reissued the whole operation as single-block PIO reads. If you get a chance to diagnose this any further, I'd be curious to know what you find. If the same problem repros with u-boot, it's almost certainly simpler to debug there. Thanks, Andrew
