On 10/11/2020 23:04, H. Nikolaus Schaller wrote: > >> Am 10.11.2020 um 17:52 schrieb Tomi Valkeinen <tomi.valkeinen@xxxxxx>: >> >> On 10/11/2020 18:49, H. Nikolaus Schaller wrote: >> >> I guess you have the same issue. It goes to dsi_bridge_mode_valid, then __dsi_calc_config, and stays >> there finding good clocks. > > Yes, I could trace it down to exactly this point. > > So the culprit is somehow the panel driver. Because it asks for clocks that the PLL driver does not want to provide... > Or is it the victim? > > Here is what dmesg reports with even more printk(): > > [ 276.970635] drm_helper_probe_single_connector_modes 12 count=1 > [ 277.003509] drm_mode_validate_pipeline 2 ret=0 status=0 > [ 277.038678] drm_bridge_chain_mode_valid: func=dsi_bridge_mode_valid+0x0/0xa0 [omapdrm] > [ 277.047199] dsi_bridge_mode_valid > [ 277.050786] __dsi_calc_config > [ 277.057270] dsi_vm_calc > [ 277.073251] dss_pll_calc_a clkin=19200000 pll_min=1555386656 pll_max=1555410656 func=dsi_vm_calc_pll_cb+0x0/0x48 [omapdrm] > [ 277.084975] dss_pll_calc_a pll_hw_max=1800000000 fint_hw_min=150000 fint_hw_max=52000000 > [ 277.093637] dss_pll_calc_a n_start=1 n_inc=1 n_stop=128 pll_max'=1555410656 > [ 277.101062] dss_pll_calc_a n=1 clkin=19200000 fint=19200000 > [ 277.107152] dss_pll_calc_a m_start=41 m_inc=1 m_stop=40 > > Ok, we have to wait quite a while until the for(m;;) loop ends, because m_stop < m_start and m_inc is positive. > > So something in the formulae in dss_pll_calc_a() does not fit or has unintended rounding effects. > Or the values reported by w677l_get_modes() do not fit anything. > > I think these findings and ideas should help to find a fix. drm_display_mode.clock is in kHz, but the panel driver writes Hz (w677l_PIXELCLOCK) to it. But there's more after fixing that. The DSI gets configured in bridge's modeset, which I think is before w677l_prepare where the panel already sends DSI commands. Also, the dsi driver fails to lock the PLL, so possibly the clock calcs are still wrong. Tomi -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
