The u-boot efi console service registers a timer to poll the keyboard input in every 50ns. In the efi block io service, this timer is evaluated on each block read, and since the timer interval is much less than the time needed to reading out a block (32kB) from the disk, the keyboard polling is therefore in the wake of each block read.
Unfortunately USB keyboard spends too much time in polling. In my test usb_kbd_poll_for_event costs 40ms in usb_kbd_testc() to test if a character is in the queue. In combination with the number of blocks to be read from the disk, the extra amound of time delayed could be around 30 seconds to load linux and initrd.
For that matters, the timer check is disabled in file loading to speed it up. The consequence would be losing the keystroke during the time file is loading, but that is acceptable IMHO.
Downstream bug reference: https://bugzilla.suse.com/show_bug.cgi?id=1171222
Signed-off-by: Michael Chang mchang@suse.com --- lib/efi_loader/efi_disk.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c index 307d5d759b..d090110b06 100644 --- a/lib/efi_loader/efi_disk.c +++ b/lib/efi_loader/efi_disk.c @@ -15,6 +15,7 @@ #include <log.h> #include <part.h> #include <malloc.h> +#include <watchdog.h>
struct efi_system_partition efi_system_partition;
@@ -103,8 +104,7 @@ static efi_status_t efi_disk_rw_blocks(struct efi_block_io *this, else n = blk_dwrite(desc, lba, blocks, buffer);
- /* We don't do interrupts, so check for timers cooperatively */ - efi_timer_check(); + WATCHDOG_RESET();
EFI_PRINT("n=%lx blocks=%x\n", n, blocks);