Re: [Nouveau] [PATCH 1/3] drm: Add separate state structure for legacy, non-KMS drivers

Hi Emil

Am 25.02.20 um 18:37 schrieb Emil Velikov:

Hi Thomas,

On Tuesday, 25 February 2020, Thomas Zimmermann <tzimmermann@suse.de mailto:tzimmermann@suse.de> wrote:

Non-KMS drivers store state in struct drm_driver. This bloats the
structure for KMS drivers and prevents it from being declared with
'static const' qualifiers. Moving the non-KMS state into a separate
data structure resolves this.

Have you considered subclassing the const drm_driver for legacy drivers. This way the legacy (pointer) data does not need to be exposed to non-legacy drivers.

I didn't want to do an upcast each time the legacy data is required. I know that subclassing is closer to the style of current DRM, but given the current code base, the additional legacy pointer seemed like the lesser evil.

Best regards Thomas

Not to mention that const data (drm_driver), which has (const) pointer to mutable data (legacy bits) is a trap IMHO

Emil