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Message-ID: <f7f912c8-65fc-e4f6-d800-04e184f1dc08@synopsys.com>
Date: Mon, 8 May 2017 11:13:37 +0100
From: Jose Abreu <Jose.Abreu@...opsys.com>
To: Daniel Vetter <daniel@...ll.ch>
CC: Jose Abreu <Jose.Abreu@...opsys.com>,
<dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
Carlos Palminha <CARLOS.PALMINHA@...opsys.com>,
Alexey Brodkin <Alexey.Brodkin@...opsys.com>,
Ville Syrjälä <ville.syrjala@...ux.intel.com>,
Dave Airlie <airlied@...ux.ie>,
Andrzej Hajda <a.hajda@...sung.com>,
Archit Taneja <architt@...eaurora.org>
Subject: Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe
helper
Hi Daniel,
On 08-05-2017 08:50, Daniel Vetter wrote:
> On Thu, May 04, 2017 at 03:11:39PM +0100, Jose Abreu wrote:
>> This changes the connector probe helper function to use the new
>> encoder->mode_valid() and crtc->mode_valid() helper callbacks to
>> validate the modes.
>>
>> The new callbacks are optional so the behaviour remains the same
>> if they are not implemented. If they are, then the code loops
>> through all the connector's encodersXcrtcs and calls the
>> callback.
>>
>> If at least a valid encoderXcrtc combination is found which
>> accepts the mode then the function returns MODE_OK.
>>
>> Signed-off-by: Jose Abreu <joabreu@...opsys.com>
>> Cc: Carlos Palminha <palminha@...opsys.com>
>> Cc: Alexey Brodkin <abrodkin@...opsys.com>
>> Cc: Ville Syrjälä <ville.syrjala@...ux.intel.com>
>> Cc: Daniel Vetter <daniel.vetter@...ll.ch>
>> Cc: Dave Airlie <airlied@...ux.ie>
>> Cc: Andrzej Hajda <a.hajda@...sung.com>
>> Cc: Archit Taneja <architt@...eaurora.org>
> A few comments below.
> -Daniel
Thanks for the review!
>
>> ---
>> drivers/gpu/drm/drm_probe_helper.c | 71 +++++++++++++++++++++++++++++++++++---
>> 1 file changed, 67 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
>> index 1b0c14a..bf19f82 100644
>> --- a/drivers/gpu/drm/drm_probe_helper.c
>> +++ b/drivers/gpu/drm/drm_probe_helper.c
>> @@ -80,6 +80,67 @@
>> return MODE_OK;
>> }
>>
>> +static enum drm_mode_status
>> +drm_mode_validate_connector(struct drm_connector *connector,
>> + struct drm_display_mode *mode)
>> +{
>> + const struct drm_connector_helper_funcs *connector_funcs =
>> + connector->helper_private;
>> + struct drm_device *dev = connector->dev;
>> + uint32_t *ids = connector->encoder_ids;
>> + enum drm_mode_status ret = MODE_OK;
>> + unsigned int i;
>> +
>> + /* Step 1: Validate against connector */
>> + if (connector_funcs && connector_funcs->mode_valid)
>> + ret = connector_funcs->mode_valid(connector, mode);
>> +
>> + if (ret != MODE_OK)
>> + return ret;
>> +
>> + /* Step 2: Validate against encoders and crtcs */
>> + for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
>> + struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
>> + const struct drm_encoder_helper_funcs *encoder_funcs;
>> + struct drm_crtc *crtc;
>> +
>> + if (!encoder)
>> + continue;
>> +
>> + encoder_funcs = encoder->helper_private;
>> + if (encoder_funcs && encoder_funcs->mode_valid)
>> + ret = encoder_funcs->mode_valid(encoder, mode);
>> + else
>> + ret = MODE_OK; /* encoder accepts everything */
>> +
>> + /* No point in continuing for crtc check as this encoder will
>> + * not accept the mode anyway. If all encoders reject the mode
>> + * then, at exit, ret will not be MODE_OK. */
>> + if (ret != MODE_OK)
>> + continue;
> I think we should validate encoders against connector->possible_ids here.
> Might be that not many drivers fill this out correctly, and in case fixing
> that is much work, perhaps as a follow-up. But would be good to at least
> help look down that part of uapi a bit more.
I'm sorry but I'm not following you here (I think I need more
coffee :)).
What do you mean by connector->possible_ids ? Is this something
new ? Because I didn't find anything in my tree and I'm based on
today's drm-next from Dave.
>
> This isn't checked within atomic and legacy helpers since we assume that
> ->best_encoder respectively ->atomic_best_encoder gives us a valid encoder
> ...
>
>> +
>> + drm_for_each_crtc(crtc, dev) {
>> + const struct drm_crtc_helper_funcs *crtc_funcs;
>> +
>> + if (!drm_encoder_crtc_ok(encoder, crtc))
>> + continue;
> We check this one here already in both atomic and legacy helpers, so all
> drivers should get this right.
But drm_for_each_crtc() iterates over all crtc from a device and
some crtcs may only be used by specific encoders (by setting
encoder->possible_crtcs), right ? We need to iterate only over
the encoder's crtc we want to validate.
>
>> +
>> + crtc_funcs = crtc->helper_private;
>> + if (!crtc_funcs || !crtc_funcs->mode_valid)
>> + return MODE_OK; /* crtc accepts everything */
>> +
>> + ret = crtc_funcs->mode_valid(crtc, mode);
>> + if (ret == MODE_OK)
>> + /* If we get to this point there is at least
>> + * one combination of encoder+crtc that works
>> + * for this mode. Lets return now. */
>> + return ret;
>> + }
>> + }
>> +
>> + return ret;
>> +}
>> +
>> static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
>> {
>> struct drm_cmdline_mode *cmdline_mode;
>> @@ -283,8 +344,10 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
>> * (if specified)
>> * - drm_mode_validate_flag() checks the modes against basic connector
>> * capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
>> - * - the optional &drm_connector_helper_funcs.mode_valid helper can perform
>> - * driver and/or hardware specific checks
>> + * - the optional &drm_connector_helper_funcs.mode_valid,
>> + * &drm_crtc_helper_funcs.mode_valid and
>> + * &drm_encoder_helper_funcs.mode_valid helpers can perform driver and/or
>> + * hardware specific checks
> I'd leave 2 bullets for connector->mode_valid (sink specific checks) and
> everything else (source checks, which are also enforced by the
> modeset/atomic helpers).
Ok, thanks!
Best regards,
Jose Miguel Abreu
>> *
>> * 5. Any mode whose status is not OK is pruned from the connector's modes list,
>> * accompanied by a debug message indicating the reason for the mode's
>> @@ -428,8 +491,8 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
>> if (mode->status == MODE_OK)
>> mode->status = drm_mode_validate_flag(mode, mode_flags);
>>
>> - if (mode->status == MODE_OK && connector_funcs->mode_valid)
>> - mode->status = connector_funcs->mode_valid(connector,
>> + if (mode->status == MODE_OK)
>> + mode->status = drm_mode_validate_connector(connector,
>> mode);
>> }
>>
>> --
>> 1.9.1
>>
>>
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