Commit 46d53e27 authored by Stanislav Lisovskiy's avatar Stanislav Lisovskiy Committed by Jani Nikula

Revert "drm/i915: Remove unneeded hack now for CDCLK"

This reverts commit 82ea174d.

Unfortunately according to our recent findings there is still some
unidentified factor, requiring CDCLK to be set higher - otherwise we
still get underruns on some multipipe configurations, despite CDCLK
being set according to BSpec formula. So getting again back into debug
mode to indentify the cause, meanwhile setting CDCLK=Pixel rate back in
order to remove regression in 10% of the cases due to FIFO underruns.
Signed-off-by: default avatarStanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Fixes: cd191546 ("drm/i915: Adjust CDCLK accordingly to our DBuf bw needs")
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200608065552.21728-1-stanislav.lisovskiy@intel.com
parent 64cf40a1
...@@ -2071,6 +2071,18 @@ int intel_crtc_compute_min_cdclk(const struct intel_crtc_state *crtc_state) ...@@ -2071,6 +2071,18 @@ int intel_crtc_compute_min_cdclk(const struct intel_crtc_state *crtc_state)
/* Account for additional needs from the planes */ /* Account for additional needs from the planes */
min_cdclk = max(intel_planes_min_cdclk(crtc_state), min_cdclk); min_cdclk = max(intel_planes_min_cdclk(crtc_state), min_cdclk);
/*
* HACK. Currently for TGL platforms we calculate
* min_cdclk initially based on pixel_rate divided
* by 2, accounting for also plane requirements,
* however in some cases the lowest possible CDCLK
* doesn't work and causing the underruns.
* Explicitly stating here that this seems to be currently
* rather a Hack, than final solution.
*/
if (IS_TIGERLAKE(dev_priv))
min_cdclk = max(min_cdclk, (int)crtc_state->pixel_rate);
if (min_cdclk > dev_priv->max_cdclk_freq) { if (min_cdclk > dev_priv->max_cdclk_freq) {
drm_dbg_kms(&dev_priv->drm, drm_dbg_kms(&dev_priv->drm,
"required cdclk (%d kHz) exceeds max (%d kHz)\n", "required cdclk (%d kHz) exceeds max (%d kHz)\n",
......
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