Igor,
Thanks for the quick response and the spreadsheet, however I still feel like I'm missing something. I used the spreadsheet to calculate a solution that appears to work (everything is marked as 'OK):
However when I add the parameters from the spreadsheet to imx8mq_ctrl_table in cdns-mdhp-hdmi-phy.c:
{ 78750, 78750, 1000, 787500, 787500, 0x03, 0x1, 0x1, 350, 0x114, 0x046, 40, 0x012, 0x012, 3150000, 3150000, 1, 2, 2, 2, 2, 0x2, 78750, 78750},
I get a new error in the boot log:
[ 3.911538] [drm] Mode: 1024x768p78750
[ 3.944789] [drm] feedback_factor: 1000
[ 3.948632] [drm] pixel_freq: 78750
[ 3.952121] [drm] Pixel clock: 78750 KHz, character clock: 78750, bpc is 8-bit.
[ 3.959438] [drm] VCO (3150000 KHz) not supported
[ 3.964155] [drm:cdns_hdmi_phy_set_imx8mq] *ERROR* failed to set phy pclock
This is because there is another table (imx8mq_pll_table) which is used to place additional restrictions on some of the parameter values (restrictions which the spreadsheet does not seem to enforce):
/* Get right row from the imx8mq_pll_table table.
* Check if vco_freq_khz and feedback_div_total
* column matching with imx8mq_pll_table. */
for (i = 0; i < ARRAY_SIZE(imx8mq_pll_table); i++) {
if (vco_freq == imx8mq_pll_table[i].vco_freq_min &&
div_total == imx8mq_pll_table[i].feedback_div_total) {
p_pll_table = &imx8mq_pll_table[i];
break;
}
}
if (i == ARRAY_SIZE(imx8mq_pll_table)) {
DRM_WARN("VCO (%d KHz) not supported\n", vco_freq);
return 0;
}
Specifically, vco_freq (D24 in the spreadsheet) and feedback_div_total (D19 in the spreadsheet) must match a line in imx8mq_pll_table to be considered ‘valid’. My solution above does not pass this test, hence the error.
I will continue to tinker around with the spreadsheet to see if I can find another solution that works, but can imx8mq_pll_table be modified to allow the solution above to function?
Thanks.
