Re: [PATCH] drm/dp: Correctly mask DP_TRAINING_AUX_RD_INTERVAL values for DP 1.4

From: Benson Leung <bleung@google.com>
To: matthew.s.atwood@intel.com
Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH] drm/dp: Correctly mask DP_TRAINING_AUX_RD_INTERVAL values for DP 1.4
Date: Wed, 7 Mar 2018 16:36:21 -0800	[thread overview]
Message-ID: <20180308003621.GA150207@decatoncale.mtv.corp.google.com> (raw)
In-Reply-To: <1520468038-11503-1-git-send-email-matthew.s.atwood@intel.com>

[-- Attachment #1.1: Type: text/plain, Size: 2658 bytes --]

Hey Matt,

Your patch doesn't build. Missing semicolon, dude.

On Wed, Mar 07, 2018 at 04:13:58PM -0800, matthew.s.atwood@intel.com wrote:
> From: Matt Atwood <matthew.s.atwood@intel.com>
> 
> DP_TRAINING_AUX_RD_INTERVAL with DP 1.3 spec changed bit scheeme from 8
> bits to 7 in DPCD 0x000e. The 8th bit is used to identify extended
> receiver capabilities. For panels that use this new feature wait interval
> would be increased by 512 ms, when spec is max 16 ms. This behavior is
> described in table 2-158 of DP 1.4 spec address 0000eh.
> 
> With the introduction of DP 1.4 spec main link clock recovery was
> standardized to 100 us regardless of TRAINING_AUX_RD_INTERVAL value.
> 
> To avoid breaking panels that are not spec compiant we now warn on
> invalid values.
> 
> V2: commit title/message, masking all 7 bits, warn on out of spec values.
> V3: commit message, make link train clock recovery follow DP 1.4 spec.
> V4: style changes
> 
> Signed-off-by: Matt Atwood <matthew.s.atwood@intel.com>
> ---
>  drivers/gpu/drm/drm_dp_helper.c | 18 ++++++++++++++----
>  include/drm/drm_dp_helper.h     |  6 ++++++
>  2 files changed, 20 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> index adf79be..6985ff3 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -119,18 +119,28 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI
>  EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis);
>  
>  void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) {
> -	if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0)
> +	int rd_interval = dpcd[DP_TRAINING_AUX_RD_INTERVAL] & DP_TRAINING_AUX_RD_MASK;
> +
> +	if (rd_interval > 4)
> +		DRM_DEBUG_KMS("AUX interval %d, out of range (max 4)", rd_interval);
> +
> +	if (rd_interval == 0 || (dpcd[DP_DPCD_REV] >= DP_REV_14))
>  		udelay(100);
>  	else
> -		mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4);
> +		mdelay(rd_interval * 4)

Need a semicolon here.

/mnt/host/source/src/third_party/kernel/v4.14/drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_link_train_clock_recovery_delay':
/mnt/host/source/src/third_party/kernel/v4.14/drivers/gpu/drm/drm_dp_helper.c:131:1: error: expected ';' before '}' token
 }
 ^
make[4]: *** [/mnt/host/source/src/third_party/kernel/v4.14/scripts/Makefile.build:320: drivers/gpu/drm/drm_dp_helper.o] Error 1

Thanks,
Benson

-- 
Benson Leung
Staff Software Engineer
Chrome OS Kernel
Google Inc.
bleung@google.com
Chromium OS Project
bleung@chromium.org

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel