Re: [PATCH] drm/meson: fix max mode_config height/width

[Neil Armstrong]

On 04/10/2018 20:10, Daniel Vetter wrote:
> On Thu, Oct 4, 2018 at 5:05 PM Neil Armstrong <narmstrong@xxxxxxxxxxxx> wrote:
>>
>> On 04/10/2018 12:09, Daniel Vetter wrote:
>>> On Thu, Oct 04, 2018 at 10:42:43AM +0200, Neil Armstrong wrote:
>>>> The mode_config max_width/max_height determines the maximum framebuffer
>>>> size the pixel reader can handle. But the values were set thinking they
>>>> were determining the maximum screen dimensions.
>>>>
>>>> This patch changes the values to the maximum height/width the CANVAS block
>>>> can handle rounded to some coherent values.
>>>>
>>>> Fixes: a41e82e6c457 ("drm/meson: Add support for components")
>>>> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
>>>
>>> It's both. Grep for all the callers of ->fill_modes and you'll see that
>>> this limit is also used to filter max screen sizes.
>>>
>>> If you want to change this, then I think we need a new
>>> mode_config.fb_max_width/height, which if non-zero, would extend the limit
>>> for fbs.
>>>
>>> There's also the problem that if you extend this for fbs, then there's no
>>> check anymore in the atomic_commit paths (or legacy modeset), so that
>>> needs to be addressed somehow too.
>>
>> What about adding optionals mode_config.fb_max_width/height and update
>> drm_internal_framebuffer_create() to use these if non-0 or fallback
>> to the mode_config max_width/max_height.
> 
> That's what I meant. Except you also need to then fix the gap you've
> opened in atomic_check, and validate the mode size against
> mode_config.max_width/height.

OK, won't this be enough ?
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -333,6 +333,8 @@ struct drm_mode_config_funcs {
  * @min_height: minimum fb pixel height on this device
  * @max_width: maximum fb pixel width on this device
  * @max_height: maximum fb pixel height on this device
+ * @max_fb_width: maximum fb buffer width if differs from max_width
+ * @max_fb_height: maximum fb buffer height if differs from max_height
  * @funcs: core driver provided mode setting functions
  * @fb_base: base address of the framebuffer
  * @poll_enabled: track polling support for this device
@@ -508,6 +510,7 @@ struct drm_mode_config {

        int min_width, min_height;
        int max_width, max_height;
+       int max_fb_width, max_fb_height;
        const struct drm_mode_config_funcs *funcs;
        resource_size_t fb_base;

--- a/drivers/gpu/drm/drm_framebuffer.c
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -283,14 +283,20 @@ drm_internal_framebuffer_create(struct drm_device *dev,
                return ERR_PTR(-EINVAL);
        }

-       if ((config->min_width > r->width) || (r->width > config->max_width)) {
+       if ((config->min_width > r->width) ||
+           (!config->max_fb_width && r->width > config->max_width) ||
+           (config->max_fb_width && r->width > config->max_fb_width)) {
                DRM_DEBUG_KMS("bad framebuffer width %d, should be >= %d && <= %d\n",
-                         r->width, config->min_width, config->max_width);
+                         r->width, config->min_width, config->max_fb_width ?
+                         config->max_fb_width : config->max_width);
                return ERR_PTR(-EINVAL);
        }
-       if ((config->min_height > r->height) || (r->height > config->max_height)) {
+       if ((config->min_height > r->height) ||
+           (!config->max_fb_height && r->height > config->max_height) ||
+           (config->max_fb_height && r->height > config->max_fb_height)) {
                DRM_DEBUG_KMS("bad framebuffer height %d, should be >= %d && <= %d\n",
-                         r->height, config->min_height, config->max_height);
+                         r->height, config->min_height, config->max_fb_height ?
+                         config->max_fb_height : config->max_height);
                return ERR_PTR(-EINVAL);
        }

and in the driver :

+       drm->mode_config.max_width = 4096;
+       drm->mode_config.max_height = 3840;
+       drm->mode_config.max_fb_width = 16384;
+       drm->mode_config.max_fb_height = 8192;

With this I leave the mode filtering intact.

Neil


> -Daniel
> 
>>
>> Neil
>>
>>>
>>> Bunch of igt to make sure we're not missing anything would be sweet on
>>> top, e.g. e.g. trying to set a mode over the limit and making sure it
>>> fails.
>>>
>>> Cheers, Daniel
>>>
>>>> ---
>>>>  drivers/gpu/drm/meson/meson_drv.c | 4 ++--
>>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
>>>> index d344312..2e29968 100644
>>>> --- a/drivers/gpu/drm/meson/meson_drv.c
>>>> +++ b/drivers/gpu/drm/meson/meson_drv.c
>>>> @@ -243,8 +243,8 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
>>>>              goto free_drm;
>>>>
>>>>      drm_mode_config_init(drm);
>>>> -    drm->mode_config.max_width = 3840;
>>>> -    drm->mode_config.max_height = 2160;
>>>> +    drm->mode_config.max_width = 16384;
>>>> +    drm->mode_config.max_height = 8192;
>>>>      drm->mode_config.funcs = &meson_mode_config_funcs;
>>>>
>>>>      /* Hardware Initialization */
>>>> --
>>>> 2.7.4
>>>>
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>>>
>>
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> 
> 
>