Files
linux-stable-mirror/drivers/gpu/drm/msm/dsi/phy
Krzysztof Kozlowski ddd8742737 drm/msm/dsi/phy_7nm: Fix missing initial VCO rate
[ Upstream commit 5ddcb0cb9d ]

Driver unconditionally saves current state on first init in
dsi_pll_7nm_init(), but does not save the VCO rate, only some of the
divider registers.  The state is then restored during probe/enable via
msm_dsi_phy_enable() -> msm_dsi_phy_pll_restore_state() ->
dsi_7nm_pll_restore_state().

Restoring calls dsi_pll_7nm_vco_set_rate() with
pll_7nm->vco_current_rate=0, which basically overwrites existing rate of
VCO and messes with clock hierarchy, by setting frequency to 0 to clock
tree.  This makes anyway little sense - VCO rate was not saved, so
should not be restored.

If PLL was not configured configure it to minimum rate to avoid glitches
and configuring entire in clock hierarchy to 0 Hz.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/657827/
Link: https://lore.kernel.org/r/20250610-b4-sm8750-display-v6-9-ee633e3ddbff@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-11-13 15:34:18 -05:00
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