Hi Andy, On 7/24/25 11:56 AM, Andy Yan wrote: > > > > Hello Cristian， > 在 2025-07-22 14:16:26，"Cristian Ciocaltea" <cristian.ciocal...@collabora.com> > 写道： >> Hi Andy, >> >> On 7/22/25 5:24 AM, Andy Yan wrote: >>> >>> Hello Cristian， >>> >>> At 2025-07-22 01:39:04, "Cristian Ciocaltea" >>> <cristian.ciocal...@collabora.com> wrote: >>>> Take the bits per color channel into consideration when computing DCLK >>>> rate. >>>> >>>> Signed-off-by: Cristian Ciocaltea <cristian.ciocal...@collabora.com> >>>> --- >>>> drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 3 +++ >>>> 1 file changed, 3 insertions(+) >>>> >>>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c >>>> b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c >>>> index >>>> 186f6452a7d359f079662bc580850929632ea8fe..a714bcbb02de16267e7febbaeb1eb270c70aaef2 >>>> 100644 >>>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c >>>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c >>>> @@ -1731,6 +1731,9 @@ static void vop2_crtc_atomic_enable(struct drm_crtc >>>> *crtc, >>>> clock *= 2; >>>> } >>>> >>>> + if (vcstate->output_bpc > 8) >>>> + clock = DIV_ROUND_CLOSEST(clock * vcstate->output_bpc, 8); >>> >>> >>> This seems not right, regardless of the value of bpc, the dclk of VOP must >>> be >>> consistent with mode->crtc_clock. >>> If the dclk of VOP is increased in accordance with the BPC ratio here, then >>> the refresh rate of VOP will also increase proportionally. >>> This would be inconsistent with the timing described in the mode. >>> For a hight color depth, the frequency needs to be increased for the HDMI >>> PHY's clock. >> >> The HDMI PHY's clock is actually computed at HDMI connector framework level >> [1], taking into account the current bpc value, which is determined as part >> of hdmi_compute_config() [2]. >> >> That means conn_state->hdmi.tmds_char_rate in >> dw_hdmi_qp_rockchip_encoder_atomic_check() does already include the bpc >> related adjustment, and we pass that directly to the PHY via >> phy_configure(). Note there's still the need to handle bpc separately via >> phy_configure_opts in order to setup CMN_REG(0086) [3]. >> >> Since VOP2 switches to PHY PLL as DCLK source for modes up to 4K@60Hz, it >> needs to take color depth into account, to keep them in sync. As a matter >> of fact, the clock adjustment in VOP2 is mainly necessary for legacy > > > There might be a misunderstanding here. The values of hdmi.tmds_char_rate and > vop dclk are not always equal in all cases. > For vop dclk always match mode->clock, hdmi.tmds_char_rate will adjust with > bpc. > For example, for a 4KP30 YUV444 8 bit, vop->dclk = hdmi.tmds_char_rate = > 297MHZ, > for 4KP30 YUV444 10 bit, hdmi.tmds_char_rate = 1.25 * vop->dclk. > > In fact, for the HDMI PHY, there are two clocks. One is a clock with the same > frequency as the HDMI PLL, namely.tmds_char_rate, > and the other is a clock obtained by further frequency division of the HDMI > PLL, which can be supplied to the vop dclk. > > ----------------------- >tmds_char_rate > | > PHY PLL------| > > | > ------DIV(REG0086[3-1])-->vop dclk.
Oh, I missed the fact there's a divider between PLL and DCLK. All this makes sense now, thanks for clarifying! Regards, Cristian > So in this case, my suggestion is still to follow the implementation of our > BSP kernel: > On the crtc side, it shoud set dclk as the mode->clock. > At the PHY side(rk_hdptx_phy_clk_set_rate) when set the vop dclk, it should > adjust the PLL clock according to the bpc: > if (bpc > 8) > bit_rate = clock * 10 / 8; > > > >> reasons, since HDPTX PHY allowed changing TMDS char rate via the Common >> Clock Framework API. We landed a proper solution for that via the HDMI PHY >> API, hence the plan would be to make CCF API readonly after the switch to >> PHY API is completed, which means VOP2 shouldn't deal anymore with clock >> calculations when using the PHY PLL as DCLK source. >> >> Regardless, I should probably move this clock adjustment to the conditional >> block handling DCLK source switch. >> >> [1] >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/display/drm_hdmi_state_helper.c?h=v6.16-rc7#n525 >> [2] >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/display/drm_hdmi_state_helper.c?h=v6.16-rc7#n608 >> [3] >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c?h=v6.16-rc7#n1034
