| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20170508075041.mj3z6572k67iv7nx@phenom.ffwll.local>
Date: Mon, 8 May 2017 09:50:41 +0200
From: Daniel Vetter <daniel@...ll.ch>
To: Jose Abreu <Jose.Abreu@...opsys.com>
Cc: 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>,
Daniel Vetter <daniel.vetter@...ll.ch>,
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
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
> ---
> 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.
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.
> +
> + 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).
> *
> * 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
>
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
Powered by blists - more mailing lists