Re: Radeon S3/resume: VGA ROM POST from kernel

["Emmanuel Thomé" <Emmanuel.Thome-MZpvjPyXg2s@public.gmane.org>]

works for me on a Dell d600, radeon 9000 M9,  (on fedora 2 kernel which
has 4G/4G patch, init_low_mapping becomes map_low). This is much better
than the patched X driver.

This has given me the opportunity to see how far the S3 status has
evolved with recent kernels on the Dell D600 hardware. Ole's patch
improves over the previous solution for the graphics resume (cleaner,
faster, and more robust). Also, the USB problems I used to have seem to
have been fixed (given the intense activity on the usb tree, it's
certainly hard to pinpoint). IOW, usability of S3 on the d600 has risen
up a lot ;-))

Many thanks,

E.

On Mon, Jul 19, 2004 at 11:31:36AM +0200, ole.rohne-vJEk5272eHo@public.gmane.org wrote:
> I've implemented VGA POSTing using a real-mode tunnel from kernel
> space. IMO, this has some advantages over user space methods:
> 
> 1. It works with the aty/radeon_pm.c resume code. I don't see how to
>    easily achieve this with user space methods.
> 2. Real mode seems faster than userspace vm86
> 3. It is the right way. Bringing up the hardware is clearly the
>    responsibility of the kernel/drivers resume code.
> 
> Ole
> 

Content-Description: patch
> diff -ru -X dontdiff linux-2.6.7/arch/i386/kernel/acpi/sleep.c linux-2.6.7-p2120/arch/i386/kernel/acpi/sleep.c
> --- linux-2.6.7/arch/i386/kernel/acpi/sleep.c	2004-07-06 21:48:04.000000000 +0200
> +++ linux-2.6.7-p2120/arch/i386/kernel/acpi/sleep.c	2004-07-19 10:53:48.000000000 +0200
> @@ -5,6 +5,7 @@
>   *  Copyright (C) 2001-2003 Pavel Machek <pavel-AlSwsSmVLrQ@public.gmane.org>
>   */
>  
> +#include <linux/module.h>
>  #include <linux/acpi.h>
>  #include <linux/bootmem.h>
>  #include <asm/smp.h>
> @@ -63,6 +64,31 @@
>  	zap_low_mappings();
>  }
>  
> +/*
> + * acpi_vgapost
> + */
> +
> +extern void do_vgapost_lowlevel (unsigned long);
> +
> +void acpi_vgapost (unsigned long slot)
> +{
> +  unsigned long flags, saved_video_flags = acpi_video_flags;
> +  acpi_video_flags = (slot & 0xffff) << 16 | 1;
> +  /* Map low memory and copy information */
> +  init_low_mapping(swapper_pg_dir, USER_PTRS_PER_PGD);
> +  memcpy((void *) acpi_wakeup_address, &wakeup_start, &wakeup_end - &wakeup_start);
> +  acpi_copy_wakeup_routine(acpi_wakeup_address);
> +  /* Tunnel thru real mode */
> +  local_irq_save(flags);
> +  do_vgapost_lowlevel(acpi_wakeup_address);
> +  local_irq_restore(flags);
> +  /* Restore mapping etc */
> +  zap_low_mappings();
> +  acpi_video_flags = saved_video_flags;
> +}
> +
> +EXPORT_SYMBOL (acpi_vgapost);
> +
>  /**
>   * acpi_reserve_bootmem - do _very_ early ACPI initialisation
>   *
> diff -ru -X dontdiff linux-2.6.7/arch/i386/kernel/acpi/wakeup.S linux-2.6.7-p2120/arch/i386/kernel/acpi/wakeup.S
> --- linux-2.6.7/arch/i386/kernel/acpi/wakeup.S	2004-07-05 19:37:21.000000000 +0200
> +++ linux-2.6.7-p2120/arch/i386/kernel/acpi/wakeup.S	2004-07-19 11:02:30.000000000 +0200
> @@ -43,6 +43,7 @@
>  
>  	testl	$1, video_flags - wakeup_code
>  	jz	1f
> +	movw	video_flags - wakeup_code + 2, %ax
>  	lcall   $0xc000,$3
>  	movw	%cs, %ax
>  	movw	%ax, %ds					# Bios might have played with that
> @@ -159,6 +160,32 @@
>  
>  _setbad: jmp setbad
>  
> +#
> +#	Real mode switch - verbatim from reboot.c
> +#
> +go_real:
> +	movl	%cr0, %eax
> +	andl	$0x00000011, %eax
> +	orl	$0x60000000, %eax
> +	movl	%eax, %cr0
> +	movl	%eax, %cr3
> +	movl	%cr0, %ebx
> +	andl	$0x60000000, %ebx
> +	jz	1f
> +	wbinvd
> +1:	andb	$0x10, %al
> +	movl	%eax, %cr0
> +go_real_jmp:		.byte	0xea
> +go_real_jmp_off:	.word	0x0000
> +go_real_jmp_seg:	.word	0x0000
> +#
> +# 	Real mode descriptor table
> +#
> +		.align	8
> +go_real_desc:	.quad	0x0000000000000000
> +go_real_cseg:	.quad	0x00009a000000ffff
> +go_real_dseg:	.quad	0x000092000000ffff
> +
>  	.code32
>  	ALIGN
>  
> @@ -284,6 +311,59 @@
>  	call acpi_enter_sleep_state_s4bios
>  	ret
>  
> +ENTRY(do_vgapost_lowlevel)
> +	# Convert target offset to physical address
> +	movl	%eax, %ecx
> +	subl	$__PAGE_OFFSET, %ecx
> +	# Fixup GDT pointer
> +	movl	%ecx, %edx
> +	addl	$go_real_desc - wakeup_start, %edx
> +	movl	%edx, go_real_gdt + 2
> +	# Fixup 16-bit CS descriptor
> +	movl	%ecx, %edx
> +	movw	%dx, go_real_cseg - wakeup_start + 2 (%eax)
> +	shrl	$16, %edx
> +	movb	%dl, go_real_cseg - wakeup_start + 4 (%eax)
> +	movb	%dh, go_real_cseg - wakeup_start + 7 (%eax)
> +	# Fixup 16-bit jump
> +	movl	%ecx, %edx
> +	shrl	$4, %edx
> +	movw	%dx, go_real_jmp_seg - wakeup_start (%eax)
> +	# Save state and registers
> +	call	save_processor_state
> +	call	save_registers
> +	# Reload page table with low mapping
> +	movl	$swapper_pg_dir-__PAGE_OFFSET, %eax
> +	movl	%eax, %cr3
> +	# Load IDTR and GDTR for real mode
> +	lidt	go_real_idt
> +	lgdt	go_real_gdt
> +	# Load DS & al
> +	movl	$0x0010, %eax
> +	movl	%eax, %ss
> +	movl	%eax, %ds
> +	movl	%eax, %es
> +	movl	%eax, %fs
> +	movl	%eax, %gs
> +	# Load CS
> +	call	$0x0008, $(go_real - wakeup_start)
> +	# Phony return code
> +	call	restore_registers
> +	call	restore_processor_state
> +	ret
> +	
> +	.align	4
> +	.word	0
> +go_real_idt:
> +	.word	0x3ff
> +	.long	0
> +	
> +	.align	4
> +	.word	0
> +go_real_gdt:
> +	.word	3*8-1
> +	.long	0
> +
>  ALIGN
>  # saved registers
>  saved_gdt:	.long	0,0
> diff -ru -X dontdiff linux-2.6.7/drivers/video/aty/radeon_pm.c linux-2.6.7-p2120/drivers/video/aty/radeon_pm.c
> --- linux-2.6.7/drivers/video/aty/radeon_pm.c	2004-07-19 10:56:15.000000000 +0200
> +++ linux-2.6.7-p2120/drivers/video/aty/radeon_pm.c	2004-07-19 10:56:34.000000000 +0200
> @@ -897,6 +897,10 @@
>  	if (pdev->dev.power_state == 0)
>  		return 0;
>  
> +	pci_restore_state (pdev, pdev->saved_config_space);
> +
> +	acpi_vgapost (pdev->devfn);
> +
>  	acquire_console_sem();
>  
>  	/* Wakeup chip */



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