Hi,
Am 28.08.20 um 08:30 schrieb Hoegeun Kwon:
On 8/27/20 6:49 PM, 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?
You are right, if use old dtb, we have a problem with the hdmi driver.
So how about modifying it like this?
@@ -1614,8 +1614,8 @@ static int vc5_hdmi_init_resources(struct vc4_hdmi *vc4_hdmi)
vc4_hdmi->pixel_bvb_clock = devm_clk_get(dev, "bvb"); if (IS_ERR(vc4_hdmi->pixel_bvb_clock)) { - DRM_ERROR("Failed to get pixel bvb clock\n"); - return PTR_ERR(vc4_hdmi->pixel_bvb_clock); + DRM_WARN("Failed to get pixel bvb clock\n"); + vc4_hdmi->pixel_bvb_clock = NULL; }
i think the better solution would be devm_clk_get_optional(), which return NULL in case the clock doesn't exist.
Best regards
vc4_hdmi->reset = devm_reset_control_get(dev, NULL);
If we modify like this, if there is no bvb clock in dtb, then pixel_bvb_clock will be null
and it will not affect the clk control function below.
- clk_set_rate() - clk_prepare_enable() - clk_disable_unprepare()
Best regards
Hoegeun