From: Stanislav Lisovskiy stanislav.lisovskiy@intel.com
commit 73a0ff0b30af79bf0303d557eb82f1d1945bb6ee upstream.
According to Bspec clock divisor registers in GeminiLake should be initialized by shifting 1(<<) to amount of correspondent divisor. While i915 was writing all this time that value as is.
Surprisingly that it by accident worked, until we met some issues with Microtech Etab.
v2: Added Fixes tag and cc v3: Added stable to cc as well.
Signed-off-by: Stanislav Lisovskiy stanislav.lisovskiy@intel.com Reviewed-by: Vandita Kulkarni vandita.kulkarni@intel.com Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108826 Fixes: bcc657004841 ("drm/i915/glk: Program txesc clock divider for GLK") Cc: Deepak M m.deepak@intel.com Cc: Madhav Chauhan madhav.chauhan@intel.com Cc: Jani Nikula jani.nikula@intel.com Cc: Jani Nikula jani.nikula@linux.intel.com Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: Rodrigo Vivi rodrigo.vivi@intel.com Cc: intel-gfx@lists.freedesktop.org Cc: stable@vger.kernel.org Signed-off-by: Jani Nikula jani.nikula@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20190712081938.14185-1-stanisl... (cherry picked from commit ce52ad5dd52cfaf3398058384e0ff94134bbd89c) Signed-off-by: Jani Nikula jani.nikula@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/i915/vlv_dsi_pll.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/i915/vlv_dsi_pll.c +++ b/drivers/gpu/drm/i915/vlv_dsi_pll.c @@ -394,8 +394,8 @@ static void glk_dsi_program_esc_clock(st else txesc2_div = 10;
- I915_WRITE(MIPIO_TXESC_CLK_DIV1, txesc1_div & GLK_TX_ESC_CLK_DIV1_MASK); - I915_WRITE(MIPIO_TXESC_CLK_DIV2, txesc2_div & GLK_TX_ESC_CLK_DIV2_MASK); + I915_WRITE(MIPIO_TXESC_CLK_DIV1, (1 << (txesc1_div - 1)) & GLK_TX_ESC_CLK_DIV1_MASK); + I915_WRITE(MIPIO_TXESC_CLK_DIV2, (1 << (txesc2_div - 1)) & GLK_TX_ESC_CLK_DIV2_MASK); }
/* Program BXT Mipi clocks and dividers */