Re: [PATCH v2] drm/i915: remove check for aux irq

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, May 23, 2018 at 11:04:35AM -0700, Lucas De Marchi wrote:
> This became dead code with commit 309bd8ed464f ("drm/i915: Reinstate
> GMBUS and AUX interrupts on gen4/g4x").
> 
> v2: Move comment about HW behavior to where decision is made to enable
> MSI (Ville).
> 
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.c  |  6 ++++++
>  drivers/gpu/drm/i915/i915_drv.h  | 10 ----------
>  drivers/gpu/drm/i915/intel_dp.c  | 22 +++++++---------------
>  drivers/gpu/drm/i915/intel_drv.h |  1 -
>  drivers/gpu/drm/i915/intel_psr.c |  2 +-
>  5 files changed, 14 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 9c449b8d8eab..a1461de20472 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1189,6 +1189,12 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
>  	 * get lost on g4x as well, and interrupt delivery seems to stay
>  	 * properly dead afterwards. So we'll just disable them for all
>  	 * pre-gen5 chipsets.
> +	 *
> +	 * dp aux and gmbus irq on gen4 seems to be able to generate legacy
> +	 * interrupts even when in MSI mode. This results in spurious
> +	 * interrupt warnings if the legacy irq no. is shared with another
> +	 * device. The kernel then disables that interrupt source and so
> +	 * prevents the other device from working properly.
>  	 */
>  	if (INTEL_GEN(dev_priv) >= 5) {
>  		if (pci_enable_msi(pdev) < 0)
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index b86ed6401120..c5e1f648c47c 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2558,16 +2558,6 @@ intel_info(const struct drm_i915_private *dev_priv)
>  	(IS_CANNONLAKE(dev_priv) || \
>  	 IS_SKL_GT3(dev_priv) || IS_SKL_GT4(dev_priv))
>  
> -/*
> - * dp aux and gmbus irq on gen4 seems to be able to generate legacy interrupts
> - * even when in MSI mode. This results in spurious interrupt warnings if the
> - * legacy irq no. is shared with another device. The kernel then disables that
> - * interrupt source and so prevents the other device from working properly.
> - *
> - * Since we don't enable MSI anymore on gen4, we can always use GMBUS/AUX
> - * interrupts.
> - */
> -#define HAS_AUX_IRQ(dev_priv)   true
>  #define HAS_GMBUS_IRQ(dev_priv) (INTEL_GEN(dev_priv) >= 4)
>  
>  /* With the 945 and later, Y tiling got adjusted so that it was 32 128-byte
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index ce07bd794aed..1dab40056df7 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -936,7 +936,7 @@ intel_dp_check_edp(struct intel_dp *intel_dp)
>  }
>  
>  static uint32_t
> -intel_dp_aux_wait_done(struct intel_dp *intel_dp, bool has_aux_irq)
> +intel_dp_aux_wait_done(struct intel_dp *intel_dp)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(intel_dp_to_dev(intel_dp));
>  	i915_reg_t ch_ctl = intel_dp->aux_ch_ctl_reg(intel_dp);
> @@ -944,14 +944,10 @@ intel_dp_aux_wait_done(struct intel_dp *intel_dp, bool has_aux_irq)
>  	bool done;
>  
>  #define C (((status = I915_READ_NOTRACE(ch_ctl)) & DP_AUX_CH_CTL_SEND_BUSY) == 0)
> -	if (has_aux_irq)
> -		done = wait_event_timeout(dev_priv->gmbus_wait_queue, C,
> -					  msecs_to_jiffies_timeout(10));
> -	else
> -		done = wait_for(C, 10) == 0;
> +	done = wait_event_timeout(dev_priv->gmbus_wait_queue, C,
> +				  msecs_to_jiffies_timeout(10));
>  	if (!done)
> -		DRM_ERROR("dp aux hw did not signal timeout (has irq: %i)!\n",
> -			  has_aux_irq);
> +		DRM_ERROR("dp aux hw did not signal timeout!\n");
>  #undef C
>  
>  	return status;
> @@ -1016,7 +1012,6 @@ static uint32_t skl_get_aux_clock_divider(struct intel_dp *intel_dp, int index)
>  }
>  
>  static uint32_t g4x_get_aux_send_ctl(struct intel_dp *intel_dp,
> -				     bool has_aux_irq,
>  				     int send_bytes,
>  				     uint32_t aux_clock_divider)
>  {
> @@ -1037,7 +1032,7 @@ static uint32_t g4x_get_aux_send_ctl(struct intel_dp *intel_dp,
>  
>  	return DP_AUX_CH_CTL_SEND_BUSY |
>  	       DP_AUX_CH_CTL_DONE |
> -	       (has_aux_irq ? DP_AUX_CH_CTL_INTERRUPT : 0) |
> +	       DP_AUX_CH_CTL_INTERRUPT |
>  	       DP_AUX_CH_CTL_TIME_OUT_ERROR |
>  	       timeout |
>  	       DP_AUX_CH_CTL_RECEIVE_ERROR |
> @@ -1047,13 +1042,12 @@ static uint32_t g4x_get_aux_send_ctl(struct intel_dp *intel_dp,
>  }
>  
>  static uint32_t skl_get_aux_send_ctl(struct intel_dp *intel_dp,
> -				      bool has_aux_irq,
>  				      int send_bytes,
>  				      uint32_t unused)
>  {
>  	return DP_AUX_CH_CTL_SEND_BUSY |
>  	       DP_AUX_CH_CTL_DONE |
> -	       (has_aux_irq ? DP_AUX_CH_CTL_INTERRUPT : 0) |
> +	       DP_AUX_CH_CTL_INTERRUPT |
>  	       DP_AUX_CH_CTL_TIME_OUT_ERROR |
>  	       DP_AUX_CH_CTL_TIME_OUT_MAX |
>  	       DP_AUX_CH_CTL_RECEIVE_ERROR |
> @@ -1076,7 +1070,6 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
>  	int i, ret, recv_bytes;
>  	uint32_t status;
>  	int try, clock = 0;
> -	bool has_aux_irq = HAS_AUX_IRQ(dev_priv);
>  	bool vdd;
>  
>  	ch_ctl = intel_dp->aux_ch_ctl_reg(intel_dp);
> @@ -1131,7 +1124,6 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
>  
>  	while ((aux_clock_divider = intel_dp->get_aux_clock_divider(intel_dp, clock++))) {
>  		u32 send_ctl = intel_dp->get_aux_send_ctl(intel_dp,
> -							  has_aux_irq,
>  							  send_bytes,
>  							  aux_clock_divider);
>  
> @@ -1148,7 +1140,7 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
>  			/* Send the command and wait for it to complete */
>  			I915_WRITE(ch_ctl, send_ctl);
>  
> -			status = intel_dp_aux_wait_done(intel_dp, has_aux_irq);
> +			status = intel_dp_aux_wait_done(intel_dp);
>  
>  			/* Clear done status and any errors */
>  			I915_WRITE(ch_ctl,
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 2855363f5b6c..7ac91d5ee3fa 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1138,7 +1138,6 @@ struct intel_dp {
>  	 * register with to kick off an AUX transaction.
>  	 */
>  	uint32_t (*get_aux_send_ctl)(struct intel_dp *dp,
> -				     bool has_aux_irq,
>  				     int send_bytes,
>  				     uint32_t aux_clock_divider);
>  
> diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
> index db27f2faa1de..ee26f5f33b87 100644
> --- a/drivers/gpu/drm/i915/intel_psr.c
> +++ b/drivers/gpu/drm/i915/intel_psr.c
> @@ -373,7 +373,7 @@ static void hsw_psr_setup_aux(struct intel_dp *intel_dp)
>  	aux_clock_divider = intel_dp->get_aux_clock_divider(intel_dp, 0);
>  
>  	/* Start with bits set for DDI_AUX_CTL register */
> -	aux_ctl = intel_dp->get_aux_send_ctl(intel_dp, 0, sizeof(aux_msg),
> +	aux_ctl = intel_dp->get_aux_send_ctl(intel_dp, sizeof(aux_msg),
>  					     aux_clock_divider);

Hmm. What's the situation with the PSR stuff here?

>  
>  	/* Select only valid bits for SRD_AUX_CTL */
> -- 
> 2.17.0

-- 
Ville Syrjälä
Intel
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