-
Notifications
You must be signed in to change notification settings - Fork 23
/
alt_buffer.c
372 lines (321 loc) · 14 KB
/
alt_buffer.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
/*
FBInk: FrameBuffer eInker, a library to print text & images to an eInk Linux framebuffer
Copyright (C) 2018-2024 NiLuJe <ninuje@gmail.com>
SPDX-License-Identifier: GPL-3.0-or-later
----
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 3 of the License, or
(at your option) 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, see <https://www.gnu.org/licenses/>.
*/
// Because we're pretty much Linux-bound ;).
#ifndef _GNU_SOURCE
# define _GNU_SOURCE
#endif
// NOTE: We need image support (chiefly for stbi__compute_y)
// A MINIMAL + IMAGE build is still recommended, because otherwise fbink_init() has to pull all the extra fonts in...
#ifdef FBINK_MINIMAL
# ifndef FBINK_WITH_IMAGE
# error Cannot build this tool without Image support!
# endif
#endif
#include <stdio.h>
#include <time.h>
// I feel dirty.
#include "../fbink.c"
// Really dirty.
#include "../qimagescale/qimagescale.c"
// Really, really dirty (for u8_cp_to_utf8).
#include "../cutef8/utf8.c"
unsigned char* altPtr = NULL;
uint32_t altAddr = 0U;
// NOTE: Wrapper around refresh_kobo to ease around API changes...
static int
refresh_kobo_compat(int fbfd, const struct mxcfb_rect region, WFM_MODE_INDEX_T waveform_mode, bool is_flashing)
{
// Increase the marker, because we're bypassing FBInk's refresh
++lastMarker;
FBInkConfig cfg = { 0 };
cfg.wfm_mode = waveform_mode;
cfg.is_flashing = is_flashing;
int ret = refresh_kobo(fbfd, region, &cfg);
return ret;
}
// NOTE: We go with the legacy ioctls for simplicity's sake.
static int
refresh_kobo_alt(int fbfd, const struct mxcfb_rect region, uint32_t waveform_mode, uint32_t update_mode)
{
// Increase the marker, because we're bypassing FBInk's refresh
++lastMarker;
// NOTE: Alternate update region dimensions must match screen update region dimensions.
// (Yes, that's a straight quote from the driver :D).
// NOTE: virt_addr seems to be unused (in fact, it's gone from newer versions of the struct).
struct mxcfb_alt_buffer_data_ntx alt = {
.virt_addr = NULL,
.phys_addr = altAddr,
.width = vInfo.xres_virtual,
.height = vInfo.yres,
.alt_update_region = region,
};
struct mxcfb_update_data_v1_ntx update = {
.update_region = region,
.waveform_mode = waveform_mode,
.update_mode = update_mode,
.update_marker = lastMarker,
.temp = TEMP_USE_AMBIENT,
.flags = (waveform_mode == WAVEFORM_MODE_REAGLD) ? EPDC_FLAG_USE_AAD
: (waveform_mode == WAVEFORM_MODE_A2) ? EPDC_FLAG_FORCE_MONOCHROME
: 0U,
.alt_buffer_data = alt,
};
// And, of course, use the alt buffer ;).
update.flags |= EPDC_FLAG_USE_ALT_BUFFER;
int rv = ioctl(fbfd, MXCFB_SEND_UPDATE_V1_NTX, &update);
if (rv < 0) {
WARN("MXCFB_SEND_UPDATE_V1_NTX w/ alt buffer: %m");
if (errno == EINVAL) {
WARN("update_region={top=%u, left=%u, width=%u, height=%u}",
region.top,
region.left,
region.width,
region.height);
}
return ERRCODE(EXIT_FAILURE);
}
return EXIT_SUCCESS;
}
// Cheap trick to get FBInk to draw to a different buffer ;).
static void
flip_draw_buffer(unsigned char* const buff_ptr)
{
fbPtr = buff_ptr;
}
int
main(void)
{
// Assume success, until shit happens ;)
int rv = EXIT_SUCCESS;
// NOTE: We're going to need a full init
FBInkConfig fbink_cfg = { 0 };
fbink_cfg.is_verbose = true;
int fbfd = -1;
// Open framebuffer and keep it around, then setup globals.
if ((fbfd = fbink_open()) == ERRCODE(EXIT_FAILURE)) {
fprintf(stderr, "Failed to open the framebuffer, aborting . . .\n");
rv = ERRCODE(EXIT_FAILURE);
goto cleanup;
}
if (fbink_init(fbfd, &fbink_cfg) != EXIT_SUCCESS) {
fprintf(stderr, "Failed to initialize FBInk, aborting . . .\n");
rv = ERRCODE(EXIT_FAILURE);
goto cleanup;
}
// We're of course going to need to mmap the fb
if (!isFbMapped) {
if (memmap_fb(fbfd) != EXIT_SUCCESS) {
rv = ERRCODE(EXIT_FAILURE);
goto cleanup;
}
}
// NOTE: We mmap the *full* fb (smem_len), so we don't need another mapping for the alt buffer,
// since it has to be *inside* the fb memory.
// NOTE: That does imply we need enough scratch space for a shadow buffer, which means 32bpp is out.
// Since no-one in their right mind should be using RGB565, that leaves 8bpp ;).
if (vInfo.bits_per_pixel != 8U) {
fprintf(stderr, "Not running @ 8bpp, not enough memory for an overlay buffer . . .\n");
rv = ERRCODE(EXIT_FAILURE);
goto cleanup;
}
// We will need an absolute pointer to the start of said buffer, which we'll compute the expected way,
// much like panning and double-buffering is supposed to work in LinuxFB (I imagine).
// NOTE: We know that yoffset is always 0, which is why we never bothered with it for fbPtr.
// So our buffer simply starts at yres_virt * line_length!
// It also ought to be exactly halfway through smem_len ;).
altPtr = fbPtr + (vInfo.yres_virtual * fInfo.line_length);
altAddr = (uint32_t) (fInfo.smem_start + (vInfo.yres_virtual * fInfo.line_length));
// Print raw pointer values...
fprintf(stdout, "fbPtr: %p vs. altPtr: %p\n", fbPtr, altPtr);
fprintf(stdout,
"altAddr: %#x (Bounds: %#zx to %#zx)\n",
altAddr,
(size_t) fInfo.smem_start,
(size_t) (fInfo.smem_start + fInfo.smem_len));
// Remember which is which, so we can easily flip to a specific draw buffer
unsigned char* const front_buffer = fbPtr;
unsigned char* const alt_buffer = altPtr;
// We start with something simple:
// Paint the front buffer white
memset(fbPtr, eInkBGCMap[0], (size_t) (fInfo.line_length * vInfo.yres));
// Paint the overlay buffer black
memset(altPtr, eInkFGCMap[0], (size_t) (fInfo.line_length * vInfo.yres));
// We'll be sleeping between tests
const struct timespec zzz = { 1L, 500 * 1e+6 };
// Our shiny marker
lastMarker = 41U;
// Refresh w/ the front buffer
struct mxcfb_rect region = { 0U };
fullscreen_region(®ion);
fprintf(stdout, "[01] White front buffer\n");
refresh_kobo_compat(fbfd, region, WFM_GC16, true);
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
// Refresh w/ the overlay buffer
fprintf(stdout, "[02] Black overlay buffer\n");
refresh_kobo_alt(fbfd, region, get_wfm_mode(WFM_GC16), UPDATE_MODE_FULL);
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
// Back to the front buffer
fprintf(stdout, "[03] White front buffer\n");
refresh_kobo_compat(fbfd, region, WFM_GC16, true);
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
// Now paint the alt buffer dark gray
// NOTE: We could also tweak a fill_rect to the right ptr if we needed more control,
// but this is good enough for a PoC ;).
memset(altPtr, eInkFGCMap[3], (size_t) (fInfo.line_length * vInfo.yres));
// And only display the bottom half of it
region.top = vInfo.yres / 2U;
region.height = vInfo.yres / 2U;
fprintf(stdout, "[04] Bottom half gray overlay buffer\n");
refresh_kobo_alt(fbfd, region, get_wfm_mode(WFM_GC16), UPDATE_MODE_FULL);
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
// Now, if we want to print a smaller region of the alt buffer, on top of the *full* front buffer,
// we have to get slightly more creative, since region & alt_region must match...
// Start by restoring the front buffer in the region we've just refreshed from the alt...
fprintf(stdout, "[05] Bottom quarter gray overlay buffer (ioctl x 2)\n");
refresh_kobo_compat(fbfd, region, WFM_GC16, true);
// Then refresh a smaller bit of the alt buffer...
region.top = vInfo.yres / 4U * 3U;
region.height = vInfo.yres / 4U;
refresh_kobo_alt(fbfd, region, get_wfm_mode(WFM_GC16), UPDATE_MODE_FULL);
// And only *now*, we wait, to hopefully let the EPDC merge those two...
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
// NOTE: In practice, getting the two to merge appears tricky, which makes the whole thing slightly less appealing...
// No matter the wfm mode, and no matter which combination of FULL/PARTIAL between the two, they won't merge,
// and the wait will block for roughly twice the amount of time as for a single update...
// NOTE: That still leaves the DIY approach of pulling the missing region from the front buffer,
// and copying it to the overlay buffer, and then updating from the overlay buffer.
// Or vice-versa...
fprintf(stdout, "[06] Bottom quarter gray overlay buffer (memcpy + ioctl)\n");
region.top = vInfo.yres / 2U;
region.height = vInfo.yres / 4U;
// Copy the third quarter slice of the screen from the front to the overlay buffer
memcpy(altPtr + (region.top * fInfo.line_length),
fbPtr + (region.top * fInfo.line_length),
region.height * fInfo.line_length);
region.top = vInfo.yres / 2U;
region.height = vInfo.yres / 2U;
// Display the spliced bottom half of the screen from the overlay buffer
refresh_kobo_alt(fbfd, region, get_wfm_mode(WFM_GC16), UPDATE_MODE_FULL);
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
// Run the double ioctl variant again, to double-check...
fprintf(stdout, "[07] Bottom quarter gray overlay buffer (ioctl x 2)\n");
refresh_kobo_compat(fbfd, region, WFM_GC16, true);
// Then refresh a smaller bit of the alt buffer...
region.top = vInfo.yres / 4U * 3U;
region.height = vInfo.yres / 4U;
refresh_kobo_alt(fbfd, region, get_wfm_mode(WFM_GC16), UPDATE_MODE_FULL);
// And only *now*, we wait, to hopefully let the EPDC merge those two...
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
// NOTE: Another approach could be to copy the (full?) front buffer to the overlay buffer *before*
// rendering the new stuff to the overlay buffer (with surgical precision, this time),
// but that's still one extra memcpy...
//
///
///
// NOTE: Once more, with feeling.
// This time, with images, both to test flipping FBInk's draw buffer,
// and confirm that there aren't any stride issues...
// NOTE: Image filenames hardcoded because I'm lazy (1.png, 2.png, 3.png).
// They should ideally be at least screen-sized ;).
fbink_cfg.ignore_alpha = true;
// We'll be handling the refreshes, of course... ;)
fbink_cfg.no_refresh = true;
// Render "1.png" to the front buffer
fprintf(stdout, "[08] Rendering 1.png to front buffer\n");
flip_draw_buffer(front_buffer); // Redundant
fbink_print_image(fbfd, "1.png", 0, 0, &fbink_cfg);
// Render "2.png" to the overlay buffer
fprintf(stdout, "[09] Rendering 2.png to overlay buffer\n");
flip_draw_buffer(alt_buffer);
fbink_print_image(fbfd, "2.png", 0, 0, &fbink_cfg);
// Refresh w/ the front buffer
fullscreen_region(®ion);
fprintf(stdout, "[10] Full front buffer\n");
refresh_kobo_compat(fbfd, region, WFM_GC16, true);
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
// Refresh w/ the overlay buffer
fprintf(stdout, "[11] Full overlay buffer\n");
refresh_kobo_alt(fbfd, region, get_wfm_mode(WFM_GC16), UPDATE_MODE_FULL);
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
// Back to the front buffer
fprintf(stdout, "[12] Full front buffer\n");
refresh_kobo_compat(fbfd, region, WFM_GC16, true);
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
// Render "3.png" to the overlay buffer
fprintf(stdout, "[13] Rendering 3.png to overlay buffer\n");
flip_draw_buffer(alt_buffer); // Redundant
fbink_print_image(fbfd, "3.png", 0, 0, &fbink_cfg);
// And only display the bottom half of it
region.top = vInfo.yres / 2U;
region.height = vInfo.yres / 2U;
fprintf(stdout, "[14] Bottom half overlay buffer\n");
refresh_kobo_alt(fbfd, region, get_wfm_mode(WFM_GC16), UPDATE_MODE_FULL);
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
// Bottom quarter of the overlay buffer, on top of the full front buffer
fprintf(stdout, "[15] Bottom quarter overlay buffer (ioctl x 2)\n");
refresh_kobo_compat(fbfd, region, WFM_GC16, true);
// Then refresh a smaller bit of the alt buffer...
region.top = vInfo.yres / 4U * 3U;
region.height = vInfo.yres / 4U;
refresh_kobo_alt(fbfd, region, get_wfm_mode(WFM_GC16), UPDATE_MODE_FULL);
// And only *now*, we wait, to hopefully let the EPDC merge those two...
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
// Same, but by splicing the fb buffers ourselves
fprintf(stdout, "[16] Bottom quarter overlay buffer (memcpy + ioctl)\n");
region.top = vInfo.yres / 2U;
region.height = vInfo.yres / 4U;
// Copy the third quarter slice of the screen from the front to the overlay buffer
// NOTE: Flip back to the front buffer first, otherwise fbPtr still == altPtr ;).
flip_draw_buffer(front_buffer);
memcpy(altPtr + (region.top * fInfo.line_length),
fbPtr + (region.top * fInfo.line_length),
region.height * fInfo.line_length);
region.top = vInfo.yres / 2U;
region.height = vInfo.yres / 2U;
// Display the spliced bottom half of the screen from the overlay buffer
refresh_kobo_alt(fbfd, region, get_wfm_mode(WFM_GC16), UPDATE_MODE_FULL);
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
// Run the double ioctl variant again, to double-check...
fprintf(stdout, "[17] Bottom quarter overlay buffer (ioctl x 2)\n");
refresh_kobo_compat(fbfd, region, WFM_GC16, true);
// Then refresh a smaller bit of the alt buffer...
region.top = vInfo.yres / 4U * 3U;
region.height = vInfo.yres / 4U;
refresh_kobo_alt(fbfd, region, get_wfm_mode(WFM_GC16), UPDATE_MODE_FULL);
// And only *now*, we wait, to hopefully let the EPDC merge those two...
fbink_wait_for_complete(fbfd, lastMarker);
nanosleep(&zzz, NULL);
cleanup:
if (fbink_close(fbfd) == ERRCODE(EXIT_FAILURE)) {
fprintf(stderr, "Failed to close the framebuffer, aborting . . .\n");
rv = ERRCODE(EXIT_FAILURE);
}
return rv;
}