Hello,
I tried if I could reproduce this issue.
(In my setup there is a tftp delivering grub installed by grub-mknetdir)
I could not get it to hang by "terminal_input at_keyboard".
But similar to what Jeroen Dekkers described I was not able anymore to
enter sane text with the keyboard. It feels like only every ~10th key
appears in grub.
(In virtualbox, qemu and on a real machine, with grub from testing
and/or a build from upstream git.)
I could track it down to calls into the PXE stack.
By avoiding these calls normal keyboard input is then still possible
when having at_keyboard loaded. (Unfortunately being then not able to
load anything via network).
By using a test function which does only the protected to real mode
switch and back without the actual PXE call, I assume the problem is
only with the mode switch itself - somehow resetting keyboard states.
------------
Attached patch (against upstream) should help in debugging the problem:
- if environment no_nic_poll is set to 1, avoid the problematic PXE call
- if environment no_nic_poll is set to 1 make only the switch from
protected mode to real and back (and avoids the problematic PXE call)
That way the keyboard input stays fluid when using this sequence:
set no_nic_poll=1
terminal_input at_keyboard
When you now unset the environment the keyboard reacts broken again:
unset no_nic_poll
(Booting would still be possible if the environment is reset just before
downloading any files)
------------
Unfortunately I was not able to reproduce it on a plain from harddisk
loaded grub.
That leaves a couple of questions open:
- have the submitter and commenter also a setup involving PXE?
- or do we have 2 or 3 different problems?
Kind regards,
Bernhard
From 39a1748cd3a4ec9e7f8e6449e3fd131143b77c05 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bernhard=20=C3=9Cbelacker?= <bernha...@vr-web.de>
Date: Thu, 18 Dec 2014 01:26:01 +0100
Subject: Help debugging debian bug #741464
---
grub-core/kern/i386/pc/startup.S | 102 +++++++++++++++++++++++-------------
grub-core/net/drivers/i386/pc/pxe.c | 7 +++
include/grub/i386/pc/pxe.h | 1 +
3 files changed, 75 insertions(+), 35 deletions(-)
diff --git a/grub-core/kern/i386/pc/startup.S b/grub-core/kern/i386/pc/startup.S
index 6bb36c6..1fc0011 100644
--- a/grub-core/kern/i386/pc/startup.S
+++ b/grub-core/kern/i386/pc/startup.S
@@ -159,42 +159,74 @@ FUNCTION(grub_exit)
* int grub_pxe_call (int func, void* data, grub_uint32_t pxe_rm_entry);
*/
FUNCTION(grub_pxe_call)
- pushl %ebp
- movl %esp, %ebp
- pushl %esi
- pushl %edi
- pushl %ebx
-
- movl %ecx, %ebx
- movl %eax, %ecx
- movl %edx, %eax
- andl $0xF, %eax
- shrl $4, %edx
- shll $16, %edx
- addl %eax, %edx
+ pushl %ebp
+ movl %esp, %ebp
+ pushl %esi
+ pushl %edi
+ pushl %ebx
+
+ movl %ecx, %ebx
+ movl %eax, %ecx
+ movl %edx, %eax
+ andl $0xF, %eax
+ shrl $4, %edx
+ shll $16, %edx
+ addl %eax, %edx
+
+ PROT_TO_REAL
+ .code16
+
+ pushl %ebx
+ pushl %edx
+ pushw %cx
+ movw %sp, %bx
+ lcall *%ss:6(%bx)
+ cld
+ addw $10, %sp
+ movw %ax, %cx
+
+ REAL_TO_PROT
+ .code32
+
+ movzwl %cx, %eax
+
+ popl %ebx
+ popl %edi
+ popl %esi
+ popl %ebp
+ ret
- PROT_TO_REAL
- .code16
-
- pushl %ebx
- pushl %edx
- pushw %cx
- movw %sp, %bx
- lcall *%ss:6(%bx)
- cld
- addw $10, %sp
- movw %ax, %cx
-
- REAL_TO_PROT
- .code32
-
- movzwl %cx, %eax
-
- popl %ebx
- popl %edi
- popl %esi
- popl %ebp
- ret
+/*
+ * int prot_to_real_to_prot (int func, void* data, grub_uint32_t pxe_rm_entry);
+ */
+FUNCTION(prot_to_real_to_prot)
+ pushl %ebp
+ movl %esp, %ebp
+ pushl %esi
+ pushl %edi
+ pushl %ebx
+
+ movl %ecx, %ebx
+ movl %eax, %ecx
+ movl %edx, %eax
+ andl $0xF, %eax
+ shrl $4, %edx
+ shll $16, %edx
+ addl %eax, %edx
+
+ PROT_TO_REAL
+ .code16
+
+ REAL_TO_PROT
+ .code32
+
+ movzwl %cx, %eax
+
+ popl %ebx
+ popl %edi
+ popl %esi
+ popl %ebp
+ ret
#include "../int.S"
diff --git a/grub-core/net/drivers/i386/pc/pxe.c b/grub-core/net/drivers/i386/pc/pxe.c
index e8c0b22..801a34c 100644
--- a/grub-core/net/drivers/i386/pc/pxe.c
+++ b/grub-core/net/drivers/i386/pc/pxe.c
@@ -180,6 +180,13 @@ grub_pxe_recv (struct grub_net_card *dev __attribute__ ((unused)))
{
grub_memset (isr, 0, sizeof (*isr));
isr->func_flag = GRUB_PXE_ISR_IN_START;
+
+ const char *debug = grub_env_get ("no_nic_poll");
+ if (debug && debug[0] >= '2')
+ prot_to_real_to_prot (GRUB_PXENV_UNDI_ISR, isr, pxe_rm_entry);
+ if (debug && debug[0] >= '1')
+ return NULL;
+
grub_pxe_call (GRUB_PXENV_UNDI_ISR, isr, pxe_rm_entry);
/* Normally according to the specification we should also check
that isr->func_flag != GRUB_PXE_ISR_OUT_OURS but unfortunately it
diff --git a/include/grub/i386/pc/pxe.h b/include/grub/i386/pc/pxe.h
index 66002bc..6b763a3 100644
--- a/include/grub/i386/pc/pxe.h
+++ b/include/grub/i386/pc/pxe.h
@@ -281,6 +281,7 @@ struct grub_pxenv_unload_stack
} GRUB_PACKED;
int EXPORT_FUNC(grub_pxe_call) (int func, void * data, grub_uint32_t pxe_rm_entry) __attribute__ ((regparm(3)));
+int EXPORT_FUNC(prot_to_real_to_prot) (int func, void * data, grub_uint32_t pxe_rm_entry) __attribute__ ((regparm(3)));
extern struct grub_pxe_bangpxe *grub_pxe_pxenv;
--
2.1.3
