Hi Stefan, On Thu, Aug 27, 2020 at 11:49:34AM +0200, Stefan Wahren wrote: > Am 27.08.20 um 06:35 schrieb Hoegeun Kwon: > > Hi Stefan, > > > > Thank you for your review. > > > > > > On 8/26/20 7:04 PM, Stefan Wahren wrote: > >> Hi Hoeguen, > >> > >> Am 21.08.20 um 09:10 schrieb Hoegeun Kwon: > >>> There is a problem that the output does not work at a resolution > >>> exceeding FHD. To solve this, we need to adjust the bvb clock at a > >>> resolution exceeding FHD. > >> this patch introduces a mandatory clock, please update > >> brcm,bcm2835-hdmi.yaml first. > >> > >> Is this clock physically available on BCM283x or only on BCM2711? > > As far as I know, BCM2711 raspberry pi 4 supports 4k, > > > > don't supported on pi 3 and pi 3+. > > > > Since 4k is not supported in versions prior to Raspberry Pi 4, > > > > I don't think we need to modify the bvb clock. > > > > > > So I think it is better to update 'brcm,bcm2711-hdmi.yaml' > > > > instead of 'brcm,bcm2835-hdmi.yaml'. > > You are correct please update only brcm,bcm2711-hdmi.yaml. > > My concern was that the function vc4_hdmi_encoder_pre_crtc_configure() > is called on a non-bcm2711 platform or on a Raspberry Pi 4 with an older > DTB. So making the BVB clock optional might be better? It won't cause any issue on a non-RPi4 platform since the clock pointer will be NULL and clk_set_rate can deal with NULL pointers just fine: https://elixir.bootlin.com/linux/latest/source/drivers/clk/clk.c#L2221 For the older DTBs, it shouldn't be an issue either. We haven't merged the binding yet, so we don't have an upstream DTB using it Maxime
