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?
Please comment, what do you think?
I'm a little bit afraid, this change could break with older firmware versions on BCM283x.
Tested it several times with libdrm modetest.
I expect there will be no problem.
Best regards,
Hoegeun
Best regards Stefan
Signed-off-by: Hoegeun Kwon hoegeun.kwon@samsung.com
drivers/gpu/drm/vc4/vc4_hdmi.c | 25 +++++++++++++++++++++++++ drivers/gpu/drm/vc4/vc4_hdmi.h | 1 + 2 files changed, 26 insertions(+)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index 95ec5eedea39..eb3192d1fd86 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -80,6 +80,7 @@ # define VC4_HD_M_ENABLE BIT(0)
#define CEC_CLOCK_FREQ 40000 +#define VC4_HSM_MID_CLOCK 149985000
static int vc4_hdmi_debugfs_regs(struct seq_file *m, void *unused) { @@ -380,6 +381,7 @@ static void vc4_hdmi_encoder_post_crtc_powerdown(struct drm_encoder *encoder) HDMI_WRITE(HDMI_VID_CTL, HDMI_READ(HDMI_VID_CTL) & ~VC4_HD_VID_CTL_ENABLE);
- clk_disable_unprepare(vc4_hdmi->pixel_bvb_clock); clk_disable_unprepare(vc4_hdmi->hsm_clock); clk_disable_unprepare(vc4_hdmi->pixel_clock);
@@ -638,6 +640,23 @@ static void vc4_hdmi_encoder_pre_crtc_configure(struct drm_encoder *encoder) return; }
- ret = clk_set_rate(vc4_hdmi->pixel_bvb_clock,
(hsm_rate > VC4_HSM_MID_CLOCK ? 150000000 : 75000000));- if (ret) {
DRM_ERROR("Failed to set pixel bvb clock rate: %d\n", ret);clk_disable_unprepare(vc4_hdmi->hsm_clock);clk_disable_unprepare(vc4_hdmi->pixel_clock);return;- }
- ret = clk_prepare_enable(vc4_hdmi->pixel_bvb_clock);
- if (ret) {
DRM_ERROR("Failed to turn on pixel bvb clock: %d\n", ret);clk_disable_unprepare(vc4_hdmi->hsm_clock);clk_disable_unprepare(vc4_hdmi->pixel_clock);return;- }
- if (vc4_hdmi->variant->reset) vc4_hdmi->variant->reset(vc4_hdmi);
@@ -1593,6 +1612,12 @@ static int vc5_hdmi_init_resources(struct vc4_hdmi *vc4_hdmi) return PTR_ERR(vc4_hdmi->audio_clock); }
- 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);- }
- vc4_hdmi->reset = devm_reset_control_get(dev, NULL); if (IS_ERR(vc4_hdmi->reset)) { DRM_ERROR("Failed to get HDMI reset line\n");
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h index 0806c6d9f24e..63c6f8bddf1d 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.h +++ b/drivers/gpu/drm/vc4/vc4_hdmi.h @@ -147,6 +147,7 @@ struct vc4_hdmi { struct clk *pixel_clock; struct clk *hsm_clock; struct clk *audio_clock;
struct clk *pixel_bvb_clock;
struct reset_control *reset;
linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel