[Letux-kernel] [Lenny400] CI20: how to boot upstream kernel?

[Ezequiel Garcia]

On Mon, 2019-05-13 at 18:14 +0200, H. Nikolaus Schaller wrote:
> Hi Mathieu,
> 
> > Am 10.05.2019 um 08:08 schrieb Mathieu Malaterre <malat at debian.org>:
> > 
> > > The 4.19 kernel is stuck with
> > > 
> > > [    0.968637] Waiting for root device /dev/mmcblk0p1...
> > > 
> > > although the mmc driver is loaded:
> > > 
> > > [    0.760598] jz4740-mmc 13460000.mmc: JZ SD/MMC card driver registered
> > > [    0.767091] jz4740-mmc 13460000.mmc: Using DMA, 4-bit mode
> > > 
> > > Before I start a bisect to find which patch between 4.19 and 5.0 made it
> > > work, I better ask the CI20 specialists here first...
> > 
> > https://patchwork.kernel.org/project/linux-mmc/list/?submitter=179601
> 
> Thanks for pointing to this patch set!
> 
> Unless I have missed something, all patches except the first one have been
> backported to stable v4.19.40 so they should be effective. And the first one
> doesn't seem to improve anything in my tests.
> 
> I have tried to git bisect and manual bisect and git log arch/mips/ingenic
> but didn't find something in the jz47xx code or CI20 drivers that is obviously
> related.
> 
> What I also tried is to cherry-pick the jz4780 dma changes introduced by
> 4.20 - but also no success.  So it might be a side-effect of some other driver.
> 
> Current status of my tests is that
> v4.20-rc2	boots to login:
> v4.20-rc1	kernel panics with page faults and strange things
> v4.19.0		fails with "waiting for root device"
> same for v4.18 and v4.14
> 
> Unfortunately, these kernel panics make it difficult to git bisect between
> v4.19 and v4.20-rc2.
> 
> It also does not seem to make a difference if I use the ci20_defconfig
> or my own (otherwise I could simply bisect the diff between both defconfigs).
> 
> Well, I could simply use 4.20-rc2 or later only, but v4.19 is currently the
> latest longterm kernel. It is the base of our LetuxOS distribution, so I'd
> prefer to get it working.
> 
> Therefore, I am a little lost in pinpointing the reason why I can't get any
> v4.19.x kernel boot properly. Is there maybe a private v4.19.x tree that is
> known to boot from SD card so that I could start comparisons?
> 

I must admit I don't have enough context here... what is the issue exactly?

Thanks,
Eze