Re: [PATCH v1 0/6] x86/boot: Enable earlyprintk on MMIO (8-bit)

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Mon, May 05, 2025 at 07:35:04AM -0700, David Woodhouse wrote:
> On Mon, 2025-05-05 at 17:05 +0300, Andy Shevchenko wrote:
> > On Fri, May 02, 2025 at 10:33:49AM -0700, David Woodhouse wrote:
> > > On Fri, 2025-05-02 at 15:29 +0300, Andy Shevchenko wrote:
> > > > Some of the platforms may have no legacy COM ports and only provide
> > > > an MMIO accessible UART. Add support for such to earlyprintk for the
> > > > boot phase of the kernel.
> > > 
> > > Shiny. I had to hack QEMU's PCI serial port to do unnatural things, in
> > > order to test the mmio32 variant which was the only thing the
> > > earlyprintk code used to support. But I *did* so, and it works with the
> > > kexec debugging.
> > > 
> > > Can you add support for this mode to the kexec debugging too, please?
> > 
> > Do you mean to add MMIO 8-bit to kexec assembly code and other parts like you
> > did in the below mentioned change?
> > 
> > I can try it at some point, but have no time right now for this.
> > I would appreciate if you can give a try for this patch series
> > functionality to see if it helps for the initial messages (as
> > far as I understand you also want to have this in the second
> > kernel, right?).
> 
> I'll see if I can find the time to take a look. Got a branch I can pull
> your series from?

Yeo, https://bitbucket.org/andy-shev/linux/commits/branch/topic%2Fx86%2Fboot-earlyprintk.


-- 
With Best Regards,
Andy Shevchenko