On Fri, Apr 19, 2013 at 08:17:10PM +0200, Daniel Vetter wrote:
> The current code is rather ... ugly. The only thing it managed to pull
> off is getting 6bpc on DP working on g4x. Then someone added another
> custom hack for 6bpc eDP on vlv. Fix up this entire mess by properly
> implementing the PIPECONF-based dither/bpc controls on g4x/vlv.
>
> Note that compared to pch based platforms g4x/vlv don't support 12bpc
> modes. g4x is already caught, extend the check for vlv.
>
> The other fixup is to restrict the lvds-specific dithering to early
> gen4 devices - g4x should use the pipeconf dither controls. Note that
> on gen2/3 the dither control is in the panel fitter even.
>
> v2: Don't enable dithering when the pipe is in 10 bpc mode. Quoting
> from Bspec "PIPEACONF - Pipe A Configuration Register, bit 4":
>
> "Programming note: Dithering should only be enabled for 8 bpc or 6
> bpc."
>
> v3: Actually drop the old ugly dither code.
>
> v4: Explain in a short comment why g4x/vlv shouldn't dither for 30 bpp
> pipes (Jesse).
>
> Signed-off-by: Daniel Vetter <daniel.vet...@ffwll.ch>
> ---
> drivers/gpu/drm/i915/intel_display.c | 35 +++++++++++++++++++++--------------
> drivers/gpu/drm/i915/intel_lvds.c | 2 +-
> 2 files changed, 22 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c
> b/drivers/gpu/drm/i915/intel_display.c
> index 8c36376..7f1ab8b 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -4605,22 +4605,29 @@ static void i9xx_set_pipeconf(struct intel_crtc
> *intel_crtc)
> pipeconf &= ~PIPECONF_DOUBLE_WIDE;
> }
>
> - /* default to 8bpc */
> - pipeconf &= ~(PIPECONF_BPC_MASK | PIPECONF_DITHER_EN);
> - if (intel_crtc->config.has_dp_encoder) {
> - if (intel_crtc->config.dither) {
> - pipeconf |= PIPECONF_6BPC |
> - PIPECONF_DITHER_EN |
> + /* only g4x and later have fancy bpc/dither controls */
> + if (IS_G4X(dev) || IS_VALLEYVIEW(dev)) {
> + pipeconf &= ~(PIPECONF_BPC_MASK | PIPECONF_DITHER_EN);
^^^^^^^^^^^^^^^^^
PIPECONF_DITHER_TYPE_MASK
The g4x docs are a bit confusing though. They seem to indicate the the
PIPECONF dither controls only affect DP.
> +
> + /* Bspec claims that we can't use dithering for 30bpp pipes. */
> + if (intel_crtc->config.dither && intel_crtc->config.pipe_bpp !=
> 30)
> + pipeconf |= PIPECONF_DITHER_EN |
> PIPECONF_DITHER_TYPE_SP;
> - }
> - }
>
> - if (IS_VALLEYVIEW(dev) && intel_pipe_has_type(&intel_crtc->base,
> - INTEL_OUTPUT_EDP)) {
> - if (intel_crtc->config.dither) {
> - pipeconf |= PIPECONF_6BPC |
> - PIPECONF_ENABLE |
> - I965_PIPECONF_ACTIVE;
> + pipeconf &= ~PIPECONF_BPC_MASK;
> + switch (intel_crtc->config.pipe_bpp) {
> + case 18:
> + pipeconf |= PIPECONF_6BPC;
> + break;
> + case 24:
> + pipeconf |= PIPECONF_8BPC;
> + break;
> + case 30:
> + pipeconf |= PIPECONF_10BPC;
> + break;
> + default:
> + /* Case prevented by intel_choose_pipe_bpp_dither. */
> + BUG();
> }
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_lvds.c
> b/drivers/gpu/drm/i915/intel_lvds.c
> index 58a98ff..094f3c5 100644
> --- a/drivers/gpu/drm/i915/intel_lvds.c
> +++ b/drivers/gpu/drm/i915/intel_lvds.c
> @@ -135,7 +135,7 @@ static void intel_pre_pll_enable_lvds(struct
> intel_encoder *encoder)
> /* Set the dithering flag on LVDS as needed, note that there is no
> * special lvds dither control bit on pch-split platforms, dithering is
> * only controlled through the PIPECONF reg. */
> - if (INTEL_INFO(dev)->gen == 4) {
> + if (INTEL_INFO(dev)->gen == 4 && !IS_G4X(dev)) {
> if (intel_crtc->config.dither)
> temp |= LVDS_ENABLE_DITHER;
> else
> --
> 1.7.11.7
>
> _______________________________________________
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> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Ville Syrjälä
Intel OTC
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