I need to make a fixed-frequency screen 800x600, the screen works well using LVDS interface in imx6, now I need to port to imx8mq using hdmi interface.
I refered to this Driving a 1080x1920 portrait HDMI screen solution.
So my solution is:
1. add below drm mode in drivers/gpu/drm/imx/hdp/imx-hdp.c
{ DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 40000, 800, 840,
850, 950, 0, 600, 603, 605, 635, 0,
DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC),
.vrefresh = 60, .picture_aspect_ratio = HDMI_PICTURE_ASPECT_16_9, },
2. uncomment the part of (VESA pixel clock rate support in debuging) in drivers/gpu/drm/imx/hdp/t28hpc_hdmitx_table.c
/* Table 8. HDMI TX clock control settings (pixel clock is output) */
const u32 t28hpc_hdmitx_clock_control_table_pixel_out[T28HPC_HDMITX_CLOCK_CONTROL_TABLE_ROWS_PIXEL_OUT][T28HPC_HDMITX_CLOCK_CONTROL_TABLE_COLS_PIXEL_OUT] = {
{ 27000, 1000, 270000, 0x03, 0x1, 0x1, 240, 0x0BC, 0x030, 80, 0x026, 0x026, 2160000, 0, 2, 2, 2, 4, 135000, 0x3, 27000, 1},
{ 27000, 1250, 337500, 0x03, 0x1, 0x1, 300, 0x0EC, 0x03C, 100, 0x030, 0x030, 2700000, 0, 2, 2, 2, 4, 168750, 0x3, 33750, 1},
{ 27000, 1500, 405000, 0x03, 0x1, 0x1, 360, 0x11C, 0x048, 120, 0x03A, 0x03A, 3240000, 0, 2, 2, 2, 4, 202500, 0x3, 40500, 1},
{ 27000, 2000, 540000, 0x03, 0x1, 0x1, 240, 0x0BC, 0x030, 80, 0x026, 0x026, 2160000, 0, 2, 2, 2, 4, 270000, 0x2, 54000, 1},
{ 54000, 1000, 540000, 0x03, 0x1, 0x1, 480, 0x17C, 0x060, 80, 0x026, 0x026, 4320000, 1, 2, 2, 2, 4, 270000, 0x3, 54000, 1},
{ 54000, 1250, 675000, 0x04, 0x1, 0x1, 400, 0x13C, 0x050, 50, 0x017, 0x017, 2700000, 0, 1, 1, 2, 4, 337500, 0x2, 67500, 1},
{ 54000, 1500, 810000, 0x04, 0x1, 0x1, 480, 0x17C, 0x060, 60, 0x01C, 0x01C, 3240000, 0, 2, 2, 2, 2, 405000, 0x2, 81000, 1},
{ 54000, 2000, 1080000, 0x03, 0x1, 0x1, 240, 0x0BC, 0x030, 40, 0x012, 0x012, 2160000, 0, 2, 2, 2, 1, 540000, 0x1, 108000, 1},
{ 74250, 1000, 742500, 0x03, 0x1, 0x1, 660, 0x20C, 0x084, 80, 0x026, 0x026, 5940000, 1, 2, 2, 2, 4, 371250, 0x3, 74250, 1},
{ 74250, 1250, 928125, 0x04, 0x1, 0x1, 550, 0x1B4, 0x06E, 50, 0x017, 0x017, 3712500, 1, 1, 1, 2, 4, 464062, 0x2, 92812, 1},
{ 74250, 1500, 1113750, 0x04, 0x1, 0x1, 660, 0x20C, 0x084, 60, 0x01C, 0x01C, 4455000, 1, 2, 2, 2, 2, 556875, 0x2, 111375, 1},
{ 74250, 2000, 1485000, 0x03, 0x1, 0x1, 330, 0x104, 0x042, 40, 0x012, 0x012, 2970000, 0, 2, 2, 2, 1, 742500, 0x1, 148500, 1},
{ 99000, 1000, 990000, 0x03, 0x1, 0x1, 440, 0x15C, 0x058, 40, 0x012, 0x012, 3960000, 1, 2, 2, 2, 2, 495000, 0x2, 99000, 1},
{ 99000, 1250, 1237500, 0x03, 0x1, 0x1, 275, 0x0D8, 0x037, 25, 0x00B, 0x00A, 2475000, 0, 1, 1, 2, 2, 618750, 0x1, 123750, 1},
{ 99000, 1500, 1485000, 0x03, 0x1, 0x1, 330, 0x104, 0x042, 30, 0x00D, 0x00D, 2970000, 0, 2, 2, 2, 1, 742500, 0x1, 148500, 1},
{ 99000, 2000, 1980000, 0x03, 0x1, 0x1, 440, 0x15C, 0x058, 40, 0x012, 0x012, 3960000, 1, 2, 2, 2, 1, 990000, 0x1, 198000, 1},
{148500, 1000, 1485000, 0x03, 0x1, 0x1, 660, 0x20C, 0x084, 40, 0x012, 0x012, 5940000, 1, 2, 2, 2, 2, 742500, 0x2, 148500, 1},
{148500, 1250, 1856250, 0x04, 0x1, 0x1, 550, 0x1B4, 0x06E, 25, 0x00B, 0x00A, 3712500, 1, 1, 1, 2, 2, 928125, 0x1, 185625, 1},
{148500, 1500, 2227500, 0x03, 0x1, 0x1, 495, 0x188, 0x063, 30, 0x00D, 0x00D, 4455000, 1, 1, 1, 2, 2, 1113750, 0x1, 222750, 1},
{148500, 2000, 2970000, 0x03, 0x1, 0x1, 660, 0x20C, 0x084, 40, 0x012, 0x012, 5940000, 1, 2, 2, 2, 1, 1485000, 0x1, 297000, 1},
{198000, 1000, 1980000, 0x03, 0x1, 0x1, 220, 0x0AC, 0x02C, 10, 0x003, 0x003, 1980000, 0, 1, 1, 2, 1, 990000, 0x0, 198000, 1},
{198000, 1250, 2475000, 0x03, 0x1, 0x1, 550, 0x1B4, 0x06E, 25, 0x00B, 0x00A, 4950000, 1, 1, 1, 2, 2, 1237500, 0x1, 247500, 1},
{198000, 1500, 2970000, 0x03, 0x1, 0x1, 330, 0x104, 0x042, 15, 0x006, 0x005, 2970000, 0, 1, 1, 2, 1, 1485000, 0x0, 297000, 1},
{198000, 2000, 3960000, 0x03, 0x1, 0x1, 440, 0x15C, 0x058, 20, 0x008, 0x008, 3960000, 1, 1, 1, 2, 1, 1980000, 0x0, 396000, 1},
{297000, 1000, 2970000, 0x03, 0x1, 0x1, 330, 0x104, 0x042, 10, 0x003, 0x003, 2970000, 0, 1, 1, 2, 1, 1485000, 0x0, 297000, 1},
{297000, 1500, 4455000, 0x03, 0x1, 0x1, 495, 0x188, 0x063, 15, 0x006, 0x005, 4455000, 1, 1, 1, 2, 1, 2227500, 0x0, 445500, 1},
{297000, 2000, 5940000, 0x03, 0x1, 0x1, 660, 0x20C, 0x084, 20, 0x008, 0x008, 5940000, 1, 1, 1, 2, 1, 2970000, 0x0, 594000, 1},
{594000, 1000, 5940000, 0x03, 0x1, 0x1, 660, 0x20C, 0x084, 10, 0x003, 0x003, 5940000, 1, 1, 1, 2, 1, 2970000, 0x0, 594000, 1},
{594000, 750, 4455000, 0x03, 0x1, 0x1, 495, 0x188, 0x063, 10, 0x003, 0x003, 4455000, 1, 1, 1, 2, 1, 2227500, 0x0, 445500, 0},
{594000, 625, 3712500, 0x04, 0x1, 0x1, 550, 0x1B4, 0x06E, 10, 0x003, 0x003, 3712500, 1, 1, 1, 2, 1, 1856250, 0x0, 371250, 0},
{594000, 500, 2970000, 0x03, 0x1, 0x1, 660, 0x20C, 0x084, 10, 0x003, 0x003, 5940000, 1, 1, 1, 2, 2, 1485000, 0x1, 297000, 1},
#if 1 /* VESA pixel clock rate support in debuging */
{ 40000, 1000, 400275, 0x05, 0x1, 0x1, 593, 0x126, 0x127, 80, 0x026, 0x026, 3202200, 1, 1, 1, 1, 1, 200137, 0x3, 40027, 1},
{ 40000, 1250, 500175, 0x05, 0x1, 0x1, 741, 0x170, 0x171, 100, 0x030, 0x030, 4001400, 1, 1, 1, 1, 1, 250087, 0x3, 50017, 1},
{ 40000, 1500, 600075, 0x05, 0x1, 0x1, 889, 0x1BA, 0x1BB, 120, 0x03A, 0x03A, 4800600, 1, 1, 1, 1, 1, 300037, 0x3, 60007, 1},
{ 40000, 2000, 800550, 0x05, 0x1, 0x1, 593, 0x126, 0x127, 80, 0x026, 0x026, 3202200, 1, 1, 1, 1, 1, 400275, 0x2, 80055, 1},
{ 65000, 1000, 650025, 0x05, 0x1, 0x1, 963, 0x1DF, 0x1E0, 80, 0x026, 0x026, 5200200, 1, 1, 1, 1, 1, 325012, 0x3, 65002, 1},
{ 65000, 1250, 812700, 0x05, 0x1, 0x1, 602, 0x12B, 0x12B, 50, 0x017, 0x017, 3250800, 1, 1, 1, 1, 1, 406350, 0x2, 81270, 1},
{ 65000, 1500, 974700, 0x05, 0x1, 0x1, 722, 0x167, 0x167, 60, 0x01C, 0x01C, 3898800, 1, 1, 1, 1, 1, 487350, 0x2, 97470, 1},
{ 65000, 2000, 1300050, 0x05, 0x1, 0x1, 963, 0x1DF, 0x1E0, 80, 0x026, 0x026, 5200200, 1, 1, 1, 1, 1, 650025, 0x2, 130005, 1},
{108000, 1000, 1080000, 0x05, 0x1, 0x1, 800, 0x18E, 0x18E, 40, 0x012, 0x012, 4320000, 1, 1, 1, 1, 1, 540000, 0x2, 108000, 1},
{108000, 1250, 1350000, 0x05, 0x1, 0x1, 1000, 0x1F2, 0x1F2, 50, 0x017, 0x017, 5400000, 1, 1, 1, 1, 1, 675000, 0x2, 135000, 1},
{108000, 1500, 1620000, 0x05, 0x1, 0x1, 600, 0x12A, 0x12A, 30, 0x00D, 0x00D, 3240000, 1, 1, 1, 1, 1, 810000, 0x1, 162000, 1},
{108000, 2000, 2160000, 0x05, 0x1, 0x1, 800, 0x18E, 0x18E, 40, 0x012, 0x012, 4320000, 1, 1, 1, 1, 1, 1080000, 0x1, 216000, 1},
{154000, 1000, 1539000, 0x05, 0x1, 0x1, 570, 0x11B, 0x11B, 20, 0x008, 0x008, 3078000, 1, 1, 1, 1, 1, 769500, 0x1, 153900, 1},
{154000, 1250, 1925100, 0x05, 0x1, 0x1, 713, 0x162, 0x163, 25, 0x00A, 0x00B, 3850200, 1, 1, 1, 1, 1, 962550, 0x1, 192510, 1},
{154000, 1500, 2311200, 0x05, 0x1, 0x1, 856, 0x1AA, 0x1AA, 30, 0x00D, 0x00D, 4622400, 1, 1, 1, 1, 1, 1155600, 0x1, 231120, 1},
{154000, 2000, 3078000, 0x05, 0x1, 0x1, 570, 0x11B, 0x11B, 20, 0x008, 0x008, 3078000, 1, 1, 1, 1, 1, 1539000, 0x0, 307800, 1}
#endif
};
After compling and programing the android image to my board. There is still no signal output.
there is below kernel information:
[ 1.399928] imx-drm display-subsystem: bound 32c00000.hdmi (ops imx_hdp_imx_ops)
[ 1.419216] [drm] Pixel clock frequency: 40000 KHz, character clock frequency: 40000, color depth is 8-bit.
[ 1.419236] [drm] Pixel clock frequency (40000 KHz) is supported in this color depth (8-bit). Settings found in row 31
[ 1.419277] [drm] VCO frequency is 3202200
[ 1.419284] [drm] VCO frequency (3202200 KHz) is supported. Settings found in row 16
[ 1.433709] [drm] CDN_API_General_Write_Register_blocking LANES_CONFIG ret = 0
As far as I know, it indicates 40M pixel clock is generated. But why there is no hdmi signal output?
Can any experts help me? Thanks very much.
There are some points I am doubt:
1. Is the 40M pixel clock out setting right in t28hpc_hdmitx_clock_control_table_pixel_out?
2. I also refer to the HDMI - pixel clock calculation.xlsx to generate the settings, but it seems the pattens are not the same with t28hpc_hdmitx_clock_control_table_pixel_out.
So how to calculate these settings in t28hpc_hdmitx_clock_control_table_pixel_out. Then how to calculate setting in t28hpc_hdmitx_pll_tuning_table_pixel_out. There are too many variables.
Thnaks.
Solved! Go to Solution.
Hi igor,
Thanks for your quick reply.
I have delt with the problem.
Br,
Edward
Hi Edward
what bsp used in the case, recommended to try latest Linux 5.10.9_1.0.0
Hdmi custom resolution example can be found on
Best regards
igor
Hi igor,
Thanks for your quick reply.
I have delt with the problem.
Br,
Edward
Hi,
It would be very kind of you if you could share video timings and modified kernel sources you have included in order to manage a 800x600 @40Mhz HDMI resolution.
Could you provide us some information about it ?
regards
Julien