On Tue, Jul 11, 2017 at 10:17 AM, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote:
> Quoting Rob Clark (2017-07-11 14:38:22)
>> +static unsigned long hijack_firmware_fb(struct drm_device *dev)
>> +{
>> + struct msm_drm_private *priv = dev->dev_private;
>> + unsigned long size;
>> + int i;
>> +
>> + /* if we have simplefb/efifb, find it's aperture and hijack
>> + * that before we kick out the firmware fb's.
>> + *
>> + * TODO we probably should hold registration_lock
>> + */
>> + for (i = 0; i < FB_MAX; i++) {
>> + struct fb_info *fb = get_fb_info(i);
>> +
>> + if (IS_ERR_OR_NULL(fb))
>> + continue;
>> +
>> + if (!fb->apertures->count)
>
> Does get_fb_info() not return a reference if its apertures->count==0?
yeah, you are right.. overlooked that when converting from iterating
registered_fb[] table directly without taking a reference..
>> + continue;
>> +
>> + /* if we find efifb or simplefb, we are about to
>> + * kick them out, so hijack their memory:
>> + */
>> + if ((strcmp(fb->fix.id, "EFI VGA") == 0) ||
>> + (strcmp(fb->fix.id, "simple") == 0)) {
>> +
>> + priv->vram.paddr = fb->apertures->ranges[0].base;
>> + size = fb->apertures->ranges[0].size;
>> + }
>> +
>> + put_fb_info(fb);
>> +
>> + if (size)
>> + return size;
>
> size is never initialised to 0. Perhaps just return the reference to the
> matching fb? Hopefully sidestepping a few of the worries about it
> disappearing during the probe.
I guess that would be a useful approach if I wanted a single helper
that did both this and kicking out firmware fb's..
BR,
-R
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