Re: [PATCH] drm/tyr: reduce size of doorbell array

[Alice Ryhl]

On Fri, Sep 11, 2026 at 1:02 AM Deborah Brouwer
<deborah.brouwer@xxxxxxxxxxxxx> wrote:
>
> Currently the number of doorbells is set to 64 which is an architectural
> maximum for the Mali GPU major v10 supported by Tyr. Since each doorbell
> needs a 64 KiB page, the doorbell array alone would need 4 MiB of register
> memory. Since the doorbell array starts at offset 0x80000, its exclusive
> end would be 0x480000, but the rk3588 device that Tyr is compatible with
> only provides a 2 MiB iomem region in total.
>
> Reduce the number of doorbells so that they fit into the rk3588 iomem
> region. This is consistent with Panthor’s doorbell id assignment.
> Doorbell 0 is the global doorbell. Panthor assigns the remaining doorbells
> to the active command stream group (CSG) slots. The number of slots is
> capped at 16 (MAX_CSG_PRIO + 1). Therefore Panthor uses a maximum of 17
> doorbells. The 17 doorbell pages span 0x110000 bytes. Since the doorbell
> array starts at offset 0x80000 its exclusive end is 0x190000 and so fits
> within the 2 MiB register region.
>
> Signed-off-by: Deborah Brouwer <deborah.brouwer@xxxxxxxxxxxxx>

Merged into drm-rust-next. Thanks!