The Detailed Timing Descriptor has only 12 bits to store the
resolution. This limits the guest to 4095 pixels.
This patch adds support for the DisplayID extension, that has 2 full
bytes for that purpose, thus allowing 5k resolutions and above.
Based-on: <20210303152948.59943-2-akihiko.od...@gmail.com>
Signed-off-by: Konstantin Nazarov <m...@knazarov.com>
---
hw/display/edid-generate.c | 156 +++++++++++++++++++++++++++++--------
hw/display/vga-pci.c | 2 +-
qemu-edid.c | 2 +-
3 files changed, 124 insertions(+), 36 deletions(-)
diff --git a/hw/display/edid-generate.c b/hw/display/edid-generate.c
index b0ce583d436..db1e319e2dc 100644
--- a/hw/display/edid-generate.c
+++ b/hw/display/edid-generate.c
@@ -44,6 +44,35 @@ static const struct edid_mode {
{ .xres = 640, .yres = 480, .byte = 35, .bit = 5 },
};
+typedef struct Timings {
+ uint32_t xfront;
+ uint32_t xsync;
+ uint32_t xblank;
+
+ uint32_t yfront;
+ uint32_t ysync;
+ uint32_t yblank;
+
+ uint64_t clock;
+} Timings;
+
+static void generate_timings(Timings *timings, uint32_t refresh_rate,
+ uint32_t xres, uint32_t yres)
+{
+ /* pull some realistic looking timings out of thin air */
+ timings->xfront = xres * 25 / 100;
+ timings->xsync = xres * 3 / 100;
+ timings->xblank = xres * 35 / 100;
+
+ timings->yfront = yres * 5 / 1000;
+ timings->ysync = yres * 5 / 1000;
+ timings->yblank = yres * 35 / 1000;
+
+ timings->clock = ((uint64_t)refresh_rate *
+ (xres + timings->xblank) *
+ (yres + timings->yblank)) / 10000000;
+}
+
static void edid_ext_dta(uint8_t *dta)
{
dta[0] = 0x02;
@@ -129,17 +158,17 @@ static void edid_fill_modes(uint8_t *edid, uint8_t
*xtra3, uint8_t *dta,
}
}
-static void edid_checksum(uint8_t *edid)
+static void edid_checksum(uint8_t *edid, size_t len)
{
uint32_t sum = 0;
int i;
- for (i = 0; i < 127; i++) {
+ for (i = 0; i < len; i++) {
sum += edid[i];
}
sum &= 0xff;
if (sum) {
- edid[127] = 0x100 - sum;
+ edid[len] = 0x100 - sum;
}
}
@@ -180,8 +209,8 @@ static void edid_desc_ranges(uint8_t *desc)
desc[7] = 30;
desc[8] = 160;
- /* max dot clock (1200 MHz) */
- desc[9] = 1200 / 10;
+ /* max dot clock (2550 MHz) */
+ desc[9] = 2550 / 10;
/* no extended timing information */
desc[10] = 0x01;
@@ -207,38 +236,29 @@ static void edid_desc_timing(uint8_t *desc, uint32_t
refresh_rate,
uint32_t xres, uint32_t yres,
uint32_t xmm, uint32_t ymm)
{
- /* pull some realistic looking timings out of thin air */
- uint32_t xfront = xres * 25 / 100;
- uint32_t xsync = xres * 3 / 100;
- uint32_t xblank = xres * 35 / 100;
-
- uint32_t yfront = yres * 5 / 1000;
- uint32_t ysync = yres * 5 / 1000;
- uint32_t yblank = yres * 35 / 1000;
-
- uint64_t clock = (uint64_t)refresh_rate * (xres + xblank) * (yres +
yblank);
-
- stl_le_p(desc, clock / 10000000);
+ Timings timings;
+ generate_timings(&timings, refresh_rate, xres, yres);
+ stl_le_p(desc, timings.clock);
desc[2] = xres & 0xff;
- desc[3] = xblank & 0xff;
+ desc[3] = timings.xblank & 0xff;
desc[4] = (((xres & 0xf00) >> 4) |
- ((xblank & 0xf00) >> 8));
+ ((timings.xblank & 0xf00) >> 8));
desc[5] = yres & 0xff;
- desc[6] = yblank & 0xff;
+ desc[6] = timings.yblank & 0xff;
desc[7] = (((yres & 0xf00) >> 4) |
- ((yblank & 0xf00) >> 8));
+ ((timings.yblank & 0xf00) >> 8));
- desc[8] = xfront & 0xff;
- desc[9] = xsync & 0xff;
+ desc[8] = timings.xfront & 0xff;
+ desc[9] = timings.xsync & 0xff;
- desc[10] = (((yfront & 0x00f) << 4) |
- ((ysync & 0x00f) << 0));
- desc[11] = (((xfront & 0x300) >> 2) |
- ((xsync & 0x300) >> 4) |
- ((yfront & 0x030) >> 2) |
- ((ysync & 0x030) >> 4));
+ desc[10] = (((timings.yfront & 0x00f) << 4) |
+ ((timings.ysync & 0x00f) << 0));
+ desc[11] = (((timings.xfront & 0x300) >> 2) |
+ ((timings.xsync & 0x300) >> 4) |
+ ((timings.yfront & 0x030) >> 2) |
+ ((timings.ysync & 0x030) >> 4));
desc[12] = xmm & 0xff;
desc[13] = ymm & 0xff;
@@ -296,15 +316,61 @@ uint32_t qemu_edid_dpi_to_mm(uint32_t dpi, uint32_t res)
return res * 254 / 10 / dpi;
}
+static void dummy_displayid(uint8_t *did)
+{
+ did[0] = 0x70; /* display id extension */
+ did[1] = 0x13; /* version 1.3 */
+ did[2] = 4; /* length */
+ did[3] = 0x03; /* product type (0x03 == standalone display device) */
+ edid_checksum(did + 1, did[2] + 4);
+}
+
+static void qemu_displayid_generate(uint8_t *did, uint32_t refresh_rate,
+ uint32_t xres, uint32_t yres,
+ uint32_t xmm, uint32_t ymm)
+{
+ Timings timings;
+ generate_timings(&timings, refresh_rate, xres, yres);
+
+ did[0] = 0x70; /* display id extension */
+ did[1] = 0x13; /* version 1.3 */
+ did[2] = 23; /* length */
+ did[3] = 0x03; /* product type (0x03 == standalone display device) */
+
+ did[5] = 0x03; /* Detailed Timings Data Block */
+ did[6] = 0x00; /* revision */
+ did[7] = 0x14; /* block length */
+
+ did[8] = timings.clock & 0xff;
+ did[9] = (timings.clock & 0xff00) >> 8;
+ did[10] = (timings.clock & 0xff0000) >> 16;
+
+ did[11] = 0x88; /* leave aspect ratio undefined */
+
+ stw_le_p(did + 12, 0xffff & (xres - 1));
+ stw_le_p(did + 14, 0xffff & (timings.xblank - 1));
+ stw_le_p(did + 16, 0xffff & (timings.xfront - 1));
+ stw_le_p(did + 18, 0xffff & (timings.xsync - 1));
+
+ stw_le_p(did + 20, 0xffff & (yres - 1));
+ stw_le_p(did + 22, 0xffff & (timings.yblank - 1));
+ stw_le_p(did + 24, 0xffff & (timings.yfront - 1));
+ stw_le_p(did + 26, 0xffff & (timings.ysync - 1));
+
+ edid_checksum(did + 1, did[2] + 4);
+}
+
void qemu_edid_generate(uint8_t *edid, size_t size,
qemu_edid_info *info)
{
uint32_t desc = 54;
uint8_t *xtra3 = NULL;
uint8_t *dta = NULL;
+ uint8_t *did = NULL;
uint32_t width_mm, height_mm;
uint32_t refresh_rate = info->refresh_rate ? info->refresh_rate : 75000;
uint32_t dpi = 100; /* if no width_mm/height_mm */
+ uint32_t large_screen = 0;
/* =============== set defaults =============== */
@@ -320,6 +386,9 @@ void qemu_edid_generate(uint8_t *edid, size_t size,
if (!info->prefy) {
info->prefy = 768;
}
+ if (info->prefx >= 4096 || info->prefy >= 4096) {
+ large_screen = 1;
+ }
if (info->width_mm && info->height_mm) {
width_mm = info->width_mm;
height_mm = info->height_mm;
@@ -401,9 +470,12 @@ void qemu_edid_generate(uint8_t *edid, size_t size,
/* =============== descriptor blocks =============== */
- edid_desc_timing(edid + desc, refresh_rate, info->prefx, info->prefy,
- width_mm, height_mm);
- desc += 18;
+ /* The DTD section has only 12 bits to store the resolution */
+ if (!large_screen) {
+ edid_desc_timing(edid + desc, refresh_rate, info->prefx, info->prefy,
+ width_mm, height_mm);
+ desc += 18;
+ }
edid_desc_ranges(edid + desc);
desc += 18;
@@ -429,12 +501,28 @@ void qemu_edid_generate(uint8_t *edid, size_t size,
desc += 18;
}
+ /* =============== display id extensions =============== */
+
+ if (size >= 384) {
+ did = edid + 256;
+ dummy_displayid(did);
+ edid[126]++;
+
+ if (large_screen) {
+ qemu_displayid_generate(did, refresh_rate, info->prefx,
info->prefy,
+ width_mm, height_mm);
+ }
+ }
+
/* =============== finish up =============== */
edid_fill_modes(edid, xtra3, dta, info->maxx, info->maxy);
- edid_checksum(edid);
+ edid_checksum(edid, 127);
if (dta) {
- edid_checksum(dta);
+ edid_checksum(dta, 127);
+ }
+ if (did) {
+ edid_checksum(did, 127);
}
}
diff --git a/hw/display/vga-pci.c b/hw/display/vga-pci.c
index 48d29630ab7..62fb5c38c1f 100644
--- a/hw/display/vga-pci.c
+++ b/hw/display/vga-pci.c
@@ -49,7 +49,7 @@ struct PCIVGAState {
qemu_edid_info edid_info;
MemoryRegion mmio;
MemoryRegion mrs[4];
- uint8_t edid[256];
+ uint8_t edid[384];
};
#define TYPE_PCI_VGA "pci-vga"
diff --git a/qemu-edid.c b/qemu-edid.c
index 1cd6a951723..028f2d181a1 100644
--- a/qemu-edid.c
+++ b/qemu-edid.c
@@ -41,7 +41,7 @@ static void usage(FILE *out)
int main(int argc, char *argv[])
{
FILE *outfile = NULL;
- uint8_t blob[256];
+ uint8_t blob[384];
uint32_t dpi = 100;
int rc;
--
2.24.3 (Apple Git-128)
