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Message-ID: <e7d78307-4a48-45b1-ffbe-bc397fec0e40@gmail.com>
Date: Wed, 10 Jul 2019 18:05:18 +0300
From: Dmitry Osipenko <digetx@...il.com>
To: Maxime Ripard <maxime.ripard@...tlin.com>
Cc: Thierry Reding <thierry.reding@...il.com>,
Jonathan Hunter <jonathanh@...dia.com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Sean Paul <sean@...rly.run>, Daniel Vetter <daniel@...ll.ch>,
David Airlie <airlied@...ux.ie>,
dri-devel@...ts.freedesktop.org, linux-tegra@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] drm/modes: Skip invalid cmdline mode
10.07.2019 17:05, Maxime Ripard пишет:
> On Wed, Jul 10, 2019 at 04:29:19PM +0300, Dmitry Osipenko wrote:
>> This works:
>>
>> diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
>> index 56d36779d213..e5a2f9c8f404 100644
>> --- a/drivers/gpu/drm/drm_client_modeset.c
>> +++ b/drivers/gpu/drm/drm_client_modeset.c
>> @@ -182,6 +182,8 @@ drm_connector_pick_cmdline_mode(struct drm_connector *connector)
>> mode = drm_mode_create_from_cmdline_mode(connector->dev, cmdline_mode);
>> if (mode)
>> list_add(&mode->head, &connector->modes);
>> + else
>> + cmdline_mode->specified = false;
>
> Hmmm, it's not clear to me why that wouldn't be the case.
>
> If we come back to the beginning of that function, we retrieve the
> cmdline_mode buffer from the connector pointer, that will probably
> have been parsed a first time using drm_mode_create_from_cmdline_mode
> in drm_helper_probe_add_cmdline_mode.
>
> Now, I'm guessing that the issue is that in
> drm_mode_parse_command_line_for_connector, if we have a named mode, we
> just copy the mode over and set mode->specified.
>
> And we then move over to do other checks, and that's probably what
> fails and returns, but our drm_cmdline_mode will have been modified.
>
> I'm not entirely sure how to deal with that though.
>
> I guess we could allocate a drm_cmdline_mode structure on the stack,
> fill that, and if successful copy over its content to the one in
> drm_connector. That would allow us to only change the content on
> success, which is what I would expect from such a function?
>
> How does that sound?
I now see that there is DRM_MODE_TYPE_USERDEF flag that is assigned only
for the "cmdline" mode and drm_client_rotation() is the only place in
DRM code that cares about whether mode is from cmdline, hence looks like
it will be more correct to do the following:
diff --git a/drivers/gpu/drm/drm_client_modeset.c
b/drivers/gpu/drm/drm_client_modeset.c
index 56d36779d213..e5b3be9ed689 100644
--- a/drivers/gpu/drm/drm_client_modeset.c
+++ b/drivers/gpu/drm/drm_client_modeset.c
@@ -825,6 +825,7 @@ bool drm_client_rotation(struct drm_mode_set
*modeset, unsigned int *rotation)
{
struct drm_connector *connector = modeset->connectors[0];
struct drm_plane *plane = modeset->crtc->primary;
+ struct drm_display_mode *mode = modeset->mode;
struct drm_cmdline_mode *cmdline;
u64 valid_mask = 0;
unsigned int i;
@@ -859,7 +860,7 @@ bool drm_client_rotation(struct drm_mode_set
*modeset, unsigned int *rotation)
* simple XOR between the two handle the addition nicely.
*/
cmdline = &connector->cmdline_mode;
- if (cmdline->specified) {
+ if (mode->flags & DRM_MODE_TYPE_USERDEF) {
unsigned int cmdline_rest, panel_rest;
unsigned int cmdline_rot, panel_rot;
unsigned int sum_rot, sum_rest;
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