60d06658f0
On the first real machine with a discrete card (an RTX 3060, 800x600 from the UEFI GOP) the console was slow enough to photograph mid-scroll, and the boot died on CPU 1's "cpu1: starting": CPU 0 spun 200M times on the console lock while CPU 1 held it, scrolling, and called it a deadlock. The framebuffer is device memory in the uncached 3-4 GB page of the direct map. QEMU's stdvga is RAM underneath, so nothing showed there; on a card, gfx_scroll_up's memmove read the whole screen back across the bus one byte at a time, and every anti-aliased glyph read back each pixel it blended. So the console now draws into a copy of the screen in RAM (vmap_alloc: kalloc pages behind a page table of their own, since nothing needs it contiguous), and gfx_flush() copies the changed rectangle onto the card through an ioremap_wc() mapping -- PAT entry 4 set to write-combining on every CPU. Flushes happen where drawing ends: a message, a terminal write, an echo, a terminal switch. Scrolling moves eight bytes at a time instead of one. /dev/fb0 reads and writes the card itself, as before. The early console's fb_info now carries the physical address it always should have. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01S1giNvrHTrPMPw7V6x1kQ4
105 lines
4.7 KiB
C
105 lines
4.7 KiB
C
#pragma once
|
|
|
|
// Drawing, and the text console under it, on whatever display is bound.
|
|
//
|
|
// This was kernel/dev/vga.c, and every consumer called it by that name:
|
|
// panic.c drew the crash screen with vga_fill_rect, the console printed with
|
|
// vga_putc, /dev/fb0 handed out vga_fb_phys(). None of that code has anything
|
|
// to do with a VGA -- it is bitmap drawing over a linear framebuffer, and the
|
|
// only VGA-specific part was where the framebuffer came from.
|
|
//
|
|
// So the driver pushes its scanout in here (gfx_attach_scanout) and everything
|
|
// above draws through these calls. A second display driver becomes a second
|
|
// caller of one function rather than an edit to the crash screen. This is the
|
|
// same arrangement as include/netdev.h, for the same reason.
|
|
//
|
|
// Not the same thing as the display class in include/display.h. That is the
|
|
// compositor's interface -- acquire a back buffer, present a rectangle, wait
|
|
// for vblank -- and it is about *frames*. This is the kernel's own drawing
|
|
// surface, used by the console and the crash screen, which do not double
|
|
// buffer and must keep working when nothing else in the system does.
|
|
|
|
// A linear framebuffer, exactly as the hardware presents it.
|
|
struct fb_info {
|
|
volatile uchar *ptr; // kernel-mapped base, or 0 if there is none
|
|
uint64 phys; // physical base, for mmap and for page tables
|
|
uint64 size; // bytes, stride * height rather than w * h * bpp
|
|
uint32 stride; // bytes per row, which may exceed width * bpp/8
|
|
uint32 bpp;
|
|
uint32 width, height;
|
|
};
|
|
|
|
// A driver publishing the framebuffer it owns. Called once, early: the console
|
|
// draws long before any bus is enumerated, so whoever owns the display the
|
|
// loader left running has to say so before then.
|
|
void gfx_attach_scanout(const struct fb_info *);
|
|
|
|
// The scanout as attached, for the few callers that need the memory itself --
|
|
// /dev/fb0 maps it, and fork copies the mapping. Returns 0 if none.
|
|
const struct fb_info *gfx_scanout(void);
|
|
|
|
int gfx_ready(void);
|
|
void gfx_dims(int *w, int *h);
|
|
uint32 gfx_width(void);
|
|
uint32 gfx_height(void);
|
|
uint64 gfx_fb_phys(void);
|
|
uint64 gfx_fb_size(void);
|
|
uint32 gfx_fb_stride(void);
|
|
uint32 gfx_fb_bpp(void);
|
|
volatile uchar *gfx_fb_ptr(void);
|
|
|
|
// The rows drawn since this was last called, for whoever is keeping a second
|
|
// screen in step with this one. Returns 0 when nothing has changed.
|
|
int gfx_damage_take(int *y0, int *y1);
|
|
|
|
// Pixels and shapes.
|
|
void gfx_draw_pixel(int x, int y, uint32 color);
|
|
void gfx_clear(uint32 color);
|
|
void gfx_fill_rect(int x, int y, int w, int h, uint32 color);
|
|
void gfx_fill_circle(int cx, int cy, int r, uint32 color);
|
|
void gfx_draw_logo(int x, int y, uint32 color, uint32 bg);
|
|
void gfx_logo_centered(int cy, uint32 color, uint32 bg);
|
|
|
|
// The built-in 8x16 font: glyphs at a position, and text that leaves the
|
|
// cursor alone. The crash screen lays itself out rather than printing, which
|
|
// is what needs the second one.
|
|
void gfx_draw_char(int x, int y, uchar c, uint32 color);
|
|
void gfx_text_at(int x, int y, const char *s, uint32 color);
|
|
int gfx_char_w(void);
|
|
int gfx_char_h(void);
|
|
|
|
// The text console: a cursor, scrolling, and the erase operations an ANSI
|
|
// escape parser needs. See kernel/core/console.c.
|
|
void gfx_putc(int c, uint32 color);
|
|
void gfx_puts(int x, int y, char *s, uint32 color);
|
|
void gfx_set_bg(uint32 color);
|
|
void gfx_screen_reset(void);
|
|
|
|
// See kernel/dev/gfx.c: drawing goes to a copy of the screen in RAM once
|
|
// gfx_accelerate() has run, and reaches the display at gfx_flush().
|
|
void gfx_accelerate(void);
|
|
void gfx_flush(void);
|
|
void gfx_flush_all(void); // the crash screen: unconditionally
|
|
volatile uchar *gfx_hw_ptr(void);
|
|
int gfx_cols(void);
|
|
int gfx_rows(void);
|
|
|
|
// For the text layer in kernel/dev/vt.c: one cell with its own colours, and
|
|
// a screen scroll that leaves the cursor alone.
|
|
// One terminal cell. `cp` is a Unicode codepoint, not a byte -- see the note on
|
|
// struct vtcell in vt.h for why that distinction is the whole feature.
|
|
void gfx_draw_cell(int col, int row, uint32 cp, uint32 fg, uint32 bg);
|
|
|
|
// Bring the console typeface up, once, early. Falls back to the built-in
|
|
// bitmap and says nothing if the font will not open -- see the note in gfx.c
|
|
// on why it cannot print for itself.
|
|
void gfx_font_init(void);
|
|
int gfx_font_ready(void);
|
|
void gfx_cell_size(int *w, int *h);
|
|
// A filled rectangle in pixels, with the per-pixel checks hoisted out.
|
|
void gfx_fill(int x, int y, int w, int h, uint32 color);
|
|
void gfx_scroll_up(uint32 bg);
|
|
void gfx_cursor_get(int *col, int *row);
|
|
void gfx_cursor_set(int col, int row);
|
|
void gfx_erase_display(int mode);
|
|
void gfx_erase_line(int mode);
|