Re: [Intel-gfx] [PATCH v3 2/7] drm/i915/dp: Use intel_dp_aux_wait_done() to wait for previous aux xfer

[Dhinakaran Pandiyan]

On Thursday, May 17, 2018 3:21:13 PM PDT José Roberto de Souza wrote:
> This reduces the spaghetti that intel_dp_aux_xfer() and reuses code.
> The only difference is that now it will wait up to 10ms instead of
> 3ms.
> 
> Cc: Dhinakaran Pandiyan 
> Cc: Rodrigo Vivi 
> Signed-off-by: José Roberto de Souza 
> ---
>  drivers/gpu/drm/i915/intel_dp.c | 20 +++-
>  1 file changed, 3 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c
> b/drivers/gpu/drm/i915/intel_dp.c index 2cc58596ff5a..b86da48fd38e 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1102,23 +1102,9 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
>   intel_dp_check_edp(intel_dp);
> 
>   /* Try to wait for any previous AUX channel activity */
> - for (try = 0; try < 3; try++) {
> - status = I915_READ_NOTRACE(ch_ctl);
> - if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0)
> - break;
> - msleep(1);
> - }
> -
> - if (try == 3) {
> - static u32 last_status = -1;
> - const u32 status = I915_READ(ch_ctl);
> -
> - if (status != last_status) {
> - WARN(1, "dp_aux_ch not started status 0x%08x\n",
> -  status);
> - last_status = status;
> - }
> -
> + status = intel_dp_aux_wait_done(intel_dp, has_aux_irq);
Isn't intel_dp_aux_wait_done(intel_dp, false) better? Assuming busy bit is set 
for HW initiated AUX transactions, the current behavior of polling for idle is 
better. 

> + if (status & DP_AUX_CH_CTL_SEND_BUSY) {
> + DRM_WARN("dp_aux_ch not started status 0x%08x\n", status);

Retain the current code to avoid log spam and fix it in a second patch with a 
per AUX channel flag?

>   ret = -EBUSY;
>   goto out;
>   }


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[Intel-gfx] [PATCH v3 2/7] drm/i915/dp: Use intel_dp_aux_wait_done() to wait for previous aux xfer

[José Roberto de Souza]

This reduces the spaghetti that intel_dp_aux_xfer() and reuses code.
The only difference is that now it will wait up to 10ms instead of
3ms.

Cc: Dhinakaran Pandiyan 
Cc: Rodrigo Vivi 
Signed-off-by: José Roberto de Souza 
---
 drivers/gpu/drm/i915/intel_dp.c | 20 +++-
 1 file changed, 3 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 2cc58596ff5a..b86da48fd38e 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1102,23 +1102,9 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
intel_dp_check_edp(intel_dp);
 
/* Try to wait for any previous AUX channel activity */
-   for (try = 0; try < 3; try++) {
-   status = I915_READ_NOTRACE(ch_ctl);
-   if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0)
-   break;
-   msleep(1);
-   }
-
-   if (try == 3) {
-   static u32 last_status = -1;
-   const u32 status = I915_READ(ch_ctl);
-
-   if (status != last_status) {
-   WARN(1, "dp_aux_ch not started status 0x%08x\n",
-status);
-   last_status = status;
-   }
-
+   status = intel_dp_aux_wait_done(intel_dp, has_aux_irq);
+   if (status & DP_AUX_CH_CTL_SEND_BUSY) {
+   DRM_WARN("dp_aux_ch not started status 0x%08x\n", status);
ret = -EBUSY;
goto out;
}
-- 
2.17.0

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