On Tue, 09 Dec 2014, Gaurav K Singh <gaurav.k.singh@xxxxxxxxx> wrote:
> Due to hardware limitations on BYT, MIPI Port C DPI Enable bit
> does not get set. To check whether DSI Port C was enabled in BIOS,
> check the Pipe B enable bit for DSI Port C. In hardware, DSI Port C
> is linked with Pipe B.
>
> v2: Addressed review comments of Jani, Nikula
> - Used platform checks for this software workaround for BYT
>
> Signed-off-by: Gaurav K Singh <gaurav.k.singh@xxxxxxxxx>
I'll take your word for the hardware limitation itself, otherwise
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_dsi.c | 22 +++++++++++++++++-----
> 1 file changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
> index 215d004..42b6d6f 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -398,8 +398,10 @@ static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,
> enum pipe *pipe)
> {
> struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
> + struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> + struct drm_device *dev = encoder->base.dev;
> enum intel_display_power_domain power_domain;
> - u32 port_ctl, func;
> + u32 dpi_enabled, func;
> enum port port;
>
> DRM_DEBUG_KMS("\n");
> @@ -409,13 +411,23 @@ static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,
> return false;
>
> /* XXX: this only works for one DSI output */
> - for_each_dsi_port(port, (1 << PORT_A) | (1 << PORT_C)) {
> - port_ctl = I915_READ(MIPI_PORT_CTRL(port));
> + for_each_dsi_port(port, intel_dsi->ports) {
> func = I915_READ(MIPI_DSI_FUNC_PRG(port));
> + dpi_enabled = I915_READ(MIPI_PORT_CTRL(port)) &
> + DPI_ENABLE;
> +
> + /* Due to some hardware limitations on BYT, MIPI Port C DPI
> + * Enable bit does not get set. To check whether DSI Port C
> + * was enabled in BIOS, check the Pipe B enable bit
> + */
> + if (IS_VALLEYVIEW(dev) && !IS_CHERRYVIEW(dev) &&
> + (port == PORT_C))
> + dpi_enabled = I915_READ(PIPECONF(PIPE_B)) &
> + PIPECONF_ENABLE;
>
> - if ((port_ctl & DPI_ENABLE) || (func & CMD_MODE_DATA_WIDTH_MASK)) {
> + if (dpi_enabled || (func & CMD_MODE_DATA_WIDTH_MASK)) {
> if (I915_READ(MIPI_DEVICE_READY(port)) & DEVICE_READY) {
> - *pipe = port == PORT_A ? PIPE_A : PIPE_C;
> + *pipe = port == PORT_A ? PIPE_A : PIPE_B;
> return true;
> }
> }
> --
> 1.7.9.5
>
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--
Jani Nikula, Intel Open Source Technology Center
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