On 7/8/21 10:22 AM, Michael Chang wrote:
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
The event is triggered every 5000 ns not 50 ns. See lib/efi_loader/efi_console.c:1309. The SetTimer() parameter is in multiples of 100 ns. UEFI spec 2.9 has this sentence: "TimerRelative: The event is to be signaled in TriggerTime 100ns units."
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
I can't imagine that Linux is that slow. Why is U-Boot so slow? Please, try to fix that code.
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.
Disabling would mean that programs like iPXE cannot react to keyboard input to interrupt a file transfer.
Best regards
Heinrich
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);