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Message-ID: <m3k0lmejlw.fsf@t19.piap.pl>
Date: Mon, 19 Jul 2021 11:30:35 +0200
From: Krzysztof Hałasa <khalasa@...p.pl>
To: Tim Harvey <tharvey@...eworks.com>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
linux-media@...r.kernel.org, lkml <linux-kernel@...r.kernel.org>
Subject: [PATCH REPOST] TDA1997x: replace video detection routine
The TDA1997x (HDMI receiver) driver currently uses a specific video
format detection scheme. The frame (or field in interlaced mode), line
and HSync pulse durations are compared to those of known, standard video
modes. If a match is found, the mode is assumed to be detected,
otherwise -ERANGE is returned (then possibly ignored). This means that:
- another mode with similar timings will be detected incorrectly
(e.g. 2x faster clock and lines twice as long)
- non-standard modes will not work.
I propose to replace this scheme with a direct read of geometry
registers. This way all modes recognized by the chip will be supported.
How does this change look like from the user's perspective?
v4l2-ctl -d $(media-ctl -e "tda19971 2-0048") --query-dv-timings
Original code - known mode: Patched:
Active width: 1152 Active width: 1152
Active height: 864 Active height: 864
Total width: 1600 Total width: 1600
Total height: 900 Total height: 900
Frame format: progressive Frame format: progressive
Polarities: +vsync +hsync Polarities: -vsync -hsync
Pixelclock: 108000000 Hz (75.00 FPS) Pixelclock: 107998200 Hz (75.00 FPS)
Horizontal frontporch: 64 Horizontal frontporch: 64
Horizontal sync: 128 Horizontal sync: 128
Horizontal backporch: 256 Horizontal backporch: 256
Vertical frontporch: 1 Vertical frontporch: 1
Vertical sync: 3 Vertical sync: 3
Vertical backporch: 32 Vertical backporch: 32
Standards: DMT Standards:
Flags: Flags:
Original code - "unknown" mode: Patched:
Active width: 0 Active width: 1400
Active height: 0 Active height: 1050
Total width: 0 Total width: 1560
Total height: 0 Total height: 1080
Frame format: progressive Frame format: progressive
Polarities: -vsync -hsync Polarities: -vsync -hsync
Pixelclock: 0 Hz Pixelclock: 79998593 Hz (47.48 FPS)
Horizontal frontporch: 0 Horizontal frontporch: 48
Horizontal sync: 0 Horizontal sync: 32
Horizontal backporch: 0 Horizontal backporch: 80
Vertical frontporch: 0 Vertical frontporch: 3
Vertical sync: 0 Vertical sync: 4
Vertical backporch: 0 Vertical backporch: 23
Standards: Standards:
Flags: Flags:
In the kernel logs - original code:
Signal Timings: 360006/399/31
Detected format: 1152x864p75.00 (1600x900)
Signal Timings: 568630/525/9
no resolution match for timings: 568630/525/9
Patched:
Signal Timings: 360006/399/31
Geometry: 1600 1152 64 128 256 900 864 1 0 3 32 0
Detected format: 1152x864p74.99 (1600x900)
Signal Timings: 568646/525/9
Geometry: 1560 1400 48 32 80 1080 1050 3 0 4 23 0
Detected format: 1400x1050p47.48 (1560x1080)
Note the differences. The original code uses values in
v4l2_dv_timings_presets[], while with the patch it reads the data from
the chip. Thus 108000000 Hz changes into (this time) 107998200 Hz.
Also, the flags. This is HDMI receiver, so I don't exactly think H and V
sync signals have any polarity (they are symbols embedded in the HDMI
stream).
I don't know if the "VESA Discrete Monitor Timings" (DMT) flag makes any
difference.
The code assumes the V sync signal has the same duration for both
fields. While this may be not necessarily true, I can't see any way to
get the "other" V sync width. This is most probably harmless.
I have checked the register values in interlaced mode, but currently
can't test such a setup (I only have remote access to a device working
in interlaced mode). Perhaps this will change in time.
All tests have been performed on Gateworks' Ventana GW54xx board, with
a TDA19971 chip.
Signed-off-by: Krzysztof Hałasa <khalasa@...p.pl>
---
... also testing UTF-8 path :-)
Krzysztof "Chris" Hałasa
Sieć Badawcza Łukasiewicz
Przemysłowy Instytut Automatyki i Pomiarów PIAP
Al. Jerozolimskie 202, 02-486 Warszawa
--- a/drivers/media/i2c/tda1997x.c
+++ b/drivers/media/i2c/tda1997x.c
@@ -1092,66 +1094,71 @@ tda1997x_detect_std(struct tda1997x_state *state,
struct v4l2_dv_timings *timings)
{
struct v4l2_subdev *sd = &state->sd;
- u32 vper;
- u16 hper;
- u16 hsper;
- int i;
/*
* Read the FMT registers
- * REG_V_PER: Period of a frame (or two fields) in MCLK(27MHz) cycles
- * REG_H_PER: Period of a line in MCLK(27MHz) cycles
- * REG_HS_WIDTH: Period of horiz sync pulse in MCLK(27MHz) cycles
+ * REG_V_PER: Period of a frame (or field) in MCLK (27MHz) cycles
+ * REG_H_PER: Period of a line in MCLK (27MHz) cycles
+ * REG_HS_WIDTH: Period of horiz sync pulse in MCLK (27MHz) cycles
*/
- vper = io_read24(sd, REG_V_PER) & MASK_VPER;
- hper = io_read16(sd, REG_H_PER) & MASK_HPER;
- hsper = io_read16(sd, REG_HS_WIDTH) & MASK_HSWIDTH;
+ u32 vper = io_read24(sd, REG_V_PER) & MASK_VPER;
+ u16 hper = io_read16(sd, REG_H_PER) & MASK_HPER;
+ u16 hswidth = io_read16(sd, REG_HS_WIDTH);
+ u16 hsper = hswidth & MASK_HSWIDTH;
+ u16 htot, hact, hfront, hsync, hback;
+ u16 vtot, vact, vfront1, vfront2, vsync, vback1, vback2;
+
v4l2_dbg(1, debug, sd, "Signal Timings: %u/%u/%u\n", vper, hper, hsper);
if (!vper || !hper || !hsper)
return -ENOLINK;
- for (i = 0; v4l2_dv_timings_presets[i].bt.width; i++) {
- const struct v4l2_bt_timings *bt;
- u32 lines, width, _hper, _hsper;
- u32 vmin, vmax, hmin, hmax, hsmin, hsmax;
- bool vmatch, hmatch, hsmatch;
-
- bt = &v4l2_dv_timings_presets[i].bt;
- width = V4L2_DV_BT_FRAME_WIDTH(bt);
- lines = V4L2_DV_BT_FRAME_HEIGHT(bt);
- _hper = (u32)bt->pixelclock / width;
- if (bt->interlaced)
- lines /= 2;
- /* vper +/- 0.7% */
- vmin = ((27000000 / 1000) * 993) / _hper * lines;
- vmax = ((27000000 / 1000) * 1007) / _hper * lines;
- /* hper +/- 1.0% */
- hmin = ((27000000 / 100) * 99) / _hper;
- hmax = ((27000000 / 100) * 101) / _hper;
- /* hsper +/- 2 (take care to avoid 32bit overflow) */
- _hsper = 27000 * bt->hsync / ((u32)bt->pixelclock/1000);
- hsmin = _hsper - 2;
- hsmax = _hsper + 2;
-
- /* vmatch matches the framerate */
- vmatch = ((vper <= vmax) && (vper >= vmin)) ? 1 : 0;
- /* hmatch matches the width */
- hmatch = ((hper <= hmax) && (hper >= hmin)) ? 1 : 0;
- /* hsmatch matches the hswidth */
- hsmatch = ((hsper <= hsmax) && (hsper >= hsmin)) ? 1 : 0;
- if (hmatch && vmatch && hsmatch) {
- v4l2_print_dv_timings(sd->name, "Detected format: ",
- &v4l2_dv_timings_presets[i],
- false);
- if (timings)
- *timings = v4l2_dv_timings_presets[i];
- return 0;
- }
+ htot = io_read16(sd, REG_FMT_H_TOT);
+ hact = io_read16(sd, REG_FMT_H_ACT);
+ hfront = io_read16(sd, REG_FMT_H_FRONT);
+ hsync = io_read16(sd, REG_FMT_H_SYNC);
+ hback = io_read16(sd, REG_FMT_H_BACK);
+
+ vtot = io_read16(sd, REG_FMT_V_TOT);
+ vact = io_read16(sd, REG_FMT_V_ACT);
+ vfront1 = io_read(sd, REG_FMT_V_FRONT_F1);
+ vfront2 = io_read(sd, REG_FMT_V_FRONT_F2);
+ vsync = io_read(sd, REG_FMT_V_SYNC);
+ vback1 = io_read(sd, REG_FMT_V_BACK_F1);
+ vback2 = io_read(sd, REG_FMT_V_BACK_F2);
+
+ v4l2_dbg(1, debug, sd, "Geometry: %u %u %u %u %u %u %u %u %u %u %u %u\n",
+ htot, hact, hfront, hsync, hback,
+ vtot, vact, vfront1, vfront2, vsync, vback1, vback2);
+
+ if (!timings)
+ return 0;
+
+ timings->type = V4L2_DV_BT_656_1120;
+ timings->bt.width = hact;
+ timings->bt.hfrontporch = hfront;
+ timings->bt.hsync = hsync;
+ timings->bt.hbackporch = hback;
+ timings->bt.height = vact;
+ timings->bt.vfrontporch = vfront1;
+ timings->bt.vsync = vsync;
+ timings->bt.vbackporch = vback1;
+ timings->bt.interlaced = hswidth & MASK_HSWIDTH_INTERLACED ?
+ V4L2_DV_INTERLACED : V4L2_DV_PROGRESSIVE;
+
+ timings->bt.pixelclock = (u64)htot * vtot * 27000000;
+ if (timings->bt.interlaced == V4L2_DV_INTERLACED) {
+ timings->bt.il_vfrontporch = vfront2;
+ timings->bt.il_vsync = timings->bt.vsync;
+ timings->bt.il_vbackporch = vback2;
+ do_div(timings->bt.pixelclock, vper * 2 /* full frame */);
+ } else {
+ timings->bt.il_vfrontporch = 0;
+ timings->bt.il_vsync = 0;
+ timings->bt.il_vbackporch = 0;
+ do_div(timings->bt.pixelclock, vper);
}
-
- v4l_err(state->client, "no resolution match for timings: %d/%d/%d\n",
- vper, hper, hsper);
- return -ERANGE;
+ v4l2_print_dv_timings(sd->name, "Detected format: ", timings, false);
+ return 0;
}
/* some sort of errata workaround for chip revision 0 (N1) */
--- a/drivers/media/i2c/tda1997x_regs.h
+++ b/drivers/media/i2c/tda1997x_regs.h
@@ -120,6 +120,7 @@
#define MASK_VHREF 0x3fff
#define MASK_HPER 0x0fff
#define MASK_HSWIDTH 0x03ff
+#define MASK_HSWIDTH_INTERLACED 0x8000
/* HPD Detection */
#define DETECT_UTIL BIT(7) /* utility of HDMI level */
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