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[vram] Add "vram" built-in setting to dump video RAM
The "vram" setting returns the (Base64-encoded) contents of video RAM,
and can be used to capture a screenshot.  For example: after running
memtest.0 and encountering an error, the output can be captured and
sent to a remote server for later diagnosis:

  #!ipxe
  chain -a http://server/memtest.0 && goto ok || goto bad
  :bad
  params
  param errno ${errno}
  param vram ${vram}
  chain -a http://server/report.php##params
  :ok

Inspired-by: Christian Nilsson <nikize@gmail.com>
Originally-implemented-by: Christian Nilsson <nikize@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
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mcb30 committed Apr 24, 2015
1 parent dc15a5a commit a25a16d
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72 changes: 72 additions & 0 deletions src/arch/x86/core/vram_settings.c
@@ -0,0 +1,72 @@
/*
* Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <ipxe/uaccess.h>
#include <ipxe/settings.h>

/** @file
*
* Video RAM dump
*
*/

/** Video RAM base address */
#define VRAM_BASE 0xb8000

/** Video RAM length */
#define VRAM_LEN \
( 80 /* columns */ * 25 /* rows */ * 2 /* bytes per character */ )

/**
* Fetch video RAM setting
*
* @v data Buffer to fill with setting data
* @v len Length of buffer
* @ret len Length of setting data, or negative error
*/
static int vram_fetch ( void *data, size_t len ) {
userptr_t vram = phys_to_user ( VRAM_BASE );

/* Copy video RAM */
if ( len > VRAM_LEN )
len = VRAM_LEN;
copy_from_user ( data, vram, 0, len );

return VRAM_LEN;
}

/** Video RAM setting */
const struct setting vram_setting __setting ( SETTING_MISC, vram ) = {
.name = "vram",
.description = "Video RAM",
.type = &setting_type_base64,
.scope = &builtin_scope,
};

/** Video RAM built-in setting */
struct builtin_setting vram_builtin_setting __builtin_setting = {
.setting = &vram_setting,
.fetch = vram_fetch,
};
3 changes: 3 additions & 0 deletions src/config/config.c
Expand Up @@ -337,6 +337,9 @@ REQUIRE_OBJECT ( cpuid_settings );
#ifdef MEMMAP_SETTINGS
REQUIRE_OBJECT ( memmap_settings );
#endif
#ifdef VRAM_SETTINGS
REQUIRE_OBJECT ( vram_settings );
#endif

/*
* Drag in selected keyboard map
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1 change: 1 addition & 0 deletions src/config/settings.h
Expand Up @@ -13,6 +13,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
//#define CPUID_SETTINGS /* CPUID settings */
//#define MEMMAP_SETTINGS /* Memory map settings */
//#define VMWARE_SETTINGS /* VMware GuestInfo settings */
//#define VRAM_SETTINGS /* Video RAM dump settings */

#include <config/named.h>
#include NAMED_CONFIG(settings.h)
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