| From 9da2d153eb010d3e92083c322e87de9ae066d93e Mon Sep 17 00:00:00 2001 |
| From: popcornmix <popcornmix@gmail.com> |
| Date: Thu, 2 Apr 2020 16:46:31 +0100 |
| Subject: [PATCH] vc4_hdmi_phy: Fix offset calculation |
| |
| The original firmware code worked with float and did |
| offset = ((vco_freq / fref * 2) * (1 << 22)); |
| offset >>= 2; |
| |
| In this code it's all integer so doing the integer divide before the shift loses lots of precision |
| |
| This fixes the issue of 1080p59.94 mode having 59.64 fps |
| |
| Signed-off-by: popcornmix <popcornmix@gmail.com> |
| --- |
| drivers/gpu/drm/vc4/vc4_hdmi_phy.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/drivers/gpu/drm/vc4/vc4_hdmi_phy.c |
| +++ b/drivers/gpu/drm/vc4/vc4_hdmi_phy.c |
| @@ -192,8 +192,8 @@ static u32 phy_get_rm_offset(unsigned lo |
| |
| /* RM offset is stored as 9.22 format */ |
| offset = vco_freq * 2; |
| - do_div(offset, fref); |
| offset = offset << 22; |
| + do_div(offset, fref); |
| offset >>= 2; |
| |
| return offset; |