Commit 8bdb3a2d authored by Michal Januszewski's avatar Michal Januszewski Committed by Linus Torvalds
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uvesafb: the driver core

uvesafb is an enhanced version of vesafb.  It uses a userspace helper (v86d)
to execute calls to the x86 Video BIOS functions.  The driver is not limited
to any specific arch and whether it works on a given arch or not depends on
that arch being supported by the userspace daemon.  It has been tested on
x86_32 and x86_64.

A single BIOS call is represented by an instance of the uvesafb_ktask
structure.  This structure contains a buffer, a completion struct and a
uvesafb_task substructure, containing the values of the x86 registers, a flags
field and a field indicating the length of the buffer.  Whenever a BIOS call
is made in the driver, uvesafb_exec() builds a message using the uvesafb_task
substructure and the contents of the buffer.  This message is then assigned a
random ack number and sent to the userspace daemon using the connector

The message's sequence number is used as an index for the uvfb_tasks array,
which provides a mapping from the messages coming from userspace to the
in-kernel uvesafb_ktask structs.

The userspace daemon performs the requested operation and sends a reply in the
form of a uvesafb_task struct and, optionally, a buffer.  The seq and ack
numbers in the reply should be exactly the same as those in the request.

Each message from userspace is processed by uvesafb_cn_callback() and after
passing a few sanity checks leads to the completion of a BIOS call request.

Signed-off-by: default avatarMichal Januszewski <>
Signed-off-by: default avatarAntonino Daplas <>
Cc: Paul Mundt <>
Cc: Paulo Marques <>
Cc: "H. Peter Anvin" <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent cc54f46e
......@@ -592,6 +592,24 @@ config FB_TGA
Say Y if you have one of those.
config FB_UVESA
tristate "Userspace VESA VGA graphics support"
depends on FB && CONNECTOR
This is the frame buffer driver for generic VBE 2.0 compliant
graphic cards. It can also take advantage of VBE 3.0 features,
such as refresh rate adjustment.
This driver generally provides more features than vesafb but
requires a userspace helper application called 'v86d'. See
<file:Documentation/fb/uvesafb.txt> for more information.
If unsure, say N.
config FB_VESA
bool "VESA VGA graphics support"
depends on (FB = y) && X86
......@@ -115,6 +115,7 @@ obj-$(CONFIG_FB_XILINX) += xilinxfb.o
obj-$(CONFIG_FB_OMAP) += omap/
# Platform or fallback drivers go here
obj-$(CONFIG_FB_UVESA) += uvesafb.o
obj-$(CONFIG_FB_VESA) += vesafb.o
obj-$(CONFIG_FB_IMAC) += imacfb.o
obj-$(CONFIG_FB_VGA16) += vga16fb.o
This diff is collapsed.
unifdef-y += sisfb.h
unifdef-y += sisfb.h uvesafb.h
#ifndef _UVESAFB_H
#define _UVESAFB_H
struct v86_regs {
__u32 ebx;
__u32 ecx;
__u32 edx;
__u32 esi;
__u32 edi;
__u32 ebp;
__u32 eax;
__u32 eip;
__u32 eflags;
__u32 esp;
__u16 cs;
__u16 ss;
__u16 es;
__u16 ds;
__u16 fs;
__u16 gs;
/* Task flags */
#define TF_VBEIB 0x01
#define TF_BUF_ESDI 0x02
#define TF_BUF_ESBX 0x04
#define TF_BUF_RET 0x08
#define TF_EXIT 0x10
struct uvesafb_task {
__u8 flags;
int buf_len;
struct v86_regs regs;
/* Constants for the capabilities field
* in vbe_ib */
#define VBE_CAP_VGACOMPAT 0x02
/* The VBE Info Block */
struct vbe_ib {
char vbe_signature[4];
__u16 vbe_version;
__u32 oem_string_ptr;
__u32 capabilities;
__u32 mode_list_ptr;
__u16 total_memory;
__u16 oem_software_rev;
__u32 oem_vendor_name_ptr;
__u32 oem_product_name_ptr;
__u32 oem_product_rev_ptr;
__u8 reserved[222];
char oem_data[256];
char misc_data[512];
} __attribute__ ((packed));
#ifdef __KERNEL__
/* VBE CRTC Info Block */
struct vbe_crtc_ib {
u16 horiz_total;
u16 horiz_start;
u16 horiz_end;
u16 vert_total;
u16 vert_start;
u16 vert_end;
u8 flags;
u32 pixel_clock;
u16 refresh_rate;
u8 reserved[40];
} __attribute__ ((packed));
#define VBE_MODE_COLOR 0x08
#define VBE_MODE_GRAPHICS 0x10
#define VBE_MODE_LFB 0x80
/* VBE Mode Info Block */
struct vbe_mode_ib {
/* for all VBE revisions */
u16 mode_attr;
u8 winA_attr;
u8 winB_attr;
u16 win_granularity;
u16 win_size;
u16 winA_seg;
u16 winB_seg;
u32 win_func_ptr;
u16 bytes_per_scan_line;
/* for VBE 1.2+ */
u16 x_res;
u16 y_res;
u8 x_char_size;
u8 y_char_size;
u8 planes;
u8 bits_per_pixel;
u8 banks;
u8 memory_model;
u8 bank_size;
u8 image_pages;
u8 reserved1;
/* Direct color fields for direct/6 and YUV/7 memory models. */
/* Offsets are bit positions of lsb in the mask. */
u8 red_len;
u8 red_off;
u8 green_len;
u8 green_off;
u8 blue_len;
u8 blue_off;
u8 rsvd_len;
u8 rsvd_off;
u8 direct_color_info; /* direct color mode attributes */
/* for VBE 2.0+ */
u32 phys_base_ptr;
u8 reserved2[6];
/* for VBE 3.0+ */
u16 lin_bytes_per_scan_line;
u8 bnk_image_pages;
u8 lin_image_pages;
u8 lin_red_len;
u8 lin_red_off;
u8 lin_green_len;
u8 lin_green_off;
u8 lin_blue_len;
u8 lin_blue_off;
u8 lin_rsvd_len;
u8 lin_rsvd_off;
u32 max_pixel_clock;
u16 mode_id;
u8 depth;
} __attribute__ ((packed));
#define UVESAFB_DEFAULT_MODE "640x480-16"
/* How long to wait for a reply from userspace [ms] */
#define UVESAFB_TIMEOUT 5000
/* Max number of concurrent tasks */
#define dac_reg (0x3c8)
#define dac_val (0x3c9)
struct uvesafb_pal_entry {
u_char blue, green, red, pad;
} __attribute__ ((packed));
struct uvesafb_ktask {
struct uvesafb_task t;
void *buf;
struct completion *done;
u32 ack;
static int uvesafb_exec(struct uvesafb_ktask *tsk);
struct uvesafb_par {
struct vbe_ib vbe_ib; /* VBE Info Block */
struct vbe_mode_ib *vbe_modes; /* list of supported VBE modes */
int vbe_modes_cnt;
u8 nocrtc;
u8 ypan; /* 0 - nothing, 1 - ypan, 2 - ywrap */
u8 pmi_setpal; /* PMI for palette changes */
u16 *pmi_base; /* protected mode interface location */
void *pmi_start;
void *pmi_pal;
u8 *vbe_state_orig; /*
* original hardware state, before the
* driver was loaded
u8 *vbe_state_saved; /* state saved by fb_save_state */
int vbe_state_size;
atomic_t ref_count;
int mode_idx;
struct vbe_crtc_ib crtc;
#endif /* __KERNEL__ */
#endif /* _UVESAFB_H */
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