Re: kernel boot fail with efi earlyprintk (bisected)

[Dave Young <dyoung@redhat.com>]

On 08/22/14 at 05:55am, Zheng, Lv wrote:
> Hi,
> 
> I checked the arch/x86/platform/efi/early_printk.c.
> In early_efi_scroll_up(), 2 mapping entries will be used for the src/dst screen buffer.
> In drivers/acpi/acpica/tbutils.c, we've improved the early table loading code in acpi_tb_parse_root_table().
> We now need 2 mapping entries:
> 1. One mapping entry is used for RSDT table mapping. Each RSDT entry contains an address for another ACPI table.
> 2. For each entry in RSDP, we need another mapping entry to map the table to perform necessary check/override before installing it.
> 
> When acpi_tb_parse_root_table() prints something through EFI earlyprintk console, we'll have 4 mapping entries used.
> The current 4 slots setting of early_ioremap() seems to be too small for such a use case.
> 
> I'm not 100% sure if this is the cause.
> If it's the cause and we think both of the mappings are reasonable, we can simply increase the FIX_BITMAPS_SLOTS defined in arch/x86/include/asm/fixmap.h.

Hmm, will give see if I can do more debug, I can try what you suggested.

Thanks
Dave