On Wed, Oct 12, 2016 at 12:37:07PM +0300, Tomi Valkeinen wrote:
> On 12/10/16 02:15, Stefan Agner wrote:
> > The current fbdev emulation does not allow to push back changes in
> > width, height or depth to KMS, hence reject any changes with an
> > error. This makes sure that fbdev ioctl's fail properly and user
> > space does not assume that changes succeeded.
>
> The description is a bit confusing. Don't you mean that currently the
> fbdev emulation does allow changes, but doesn't actually push those
> changes to KMS? And this patch makes the driver reject those changes.
>
> The change itself sounds good to me.
>
> Reviewed-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
Applied to drm-misc, thanks.
-Daniel
>
> > Signed-off-by: Stefan Agner <stefan at agner.ch>
> > ---
> > This rejects reconfiguration of framebuffer like
> > fbset -rgba 5,6,5 -depth 16 (when in 24 bit mode by default)
> > fbset -xres 123
> >
> > I think all users of drm_fb_helper_check_var use also the generic
> > drm_fb_helper_set_par (or do otherwise not support changing size/
> > depth). Hence, afaict, the change should be the right thing to do
> > for all driver...
> >
> > drivers/gpu/drm/drm_fb_helper.c | 13 ++++++++-----
> > 1 file changed, 8 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_fb_helper.c
> > b/drivers/gpu/drm/drm_fb_helper.c
> > index 03414bd..596c056 100644
> > --- a/drivers/gpu/drm/drm_fb_helper.c
> > +++ b/drivers/gpu/drm/drm_fb_helper.c
> > @@ -1211,11 +1211,14 @@ int drm_fb_helper_check_var(struct
> > fb_var_screeninfo *var,
> > if (var->pixclock != 0 || in_dbg_master())
> > return -EINVAL;
> >
> > - /* Need to resize the fb object !!! */
> > - if (var->bits_per_pixel > fb->bits_per_pixel ||
> > - var->xres > fb->width || var->yres > fb->height ||
> > - var->xres_virtual > fb->width || var->yres_virtual > fb->height) {
> > - DRM_DEBUG("fb userspace requested width/height/bpp is greater
> > than current fb "
> > + /*
> > + * Changes struct fb_var_screeninfo are currently not pushed back
> > + * to KMS, hence fail if different settings are requested.
> > + */
> > + if (var->bits_per_pixel != fb->bits_per_pixel ||
> > + var->xres != fb->width || var->yres != fb->height ||
> > + var->xres_virtual != fb->width || var->yres_virtual != fb->height) {
> > + DRM_DEBUG("fb userspace requested width/height/bpp different
> > than current fb "
> > "request %dx%d-%d (virtual %dx%d) > %dx%d-%d\n",
> > var->xres, var->yres, var->bits_per_pixel,
> > var->xres_virtual, var->yres_virtual,
> >
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
