Some Broadcom V3D Graphics Support On Path For Removed Over Lack Of Testing
([Hardware] 6 Hours Ago
Broadcom V3D)
- Reference: 0001638612
- News link: https://www.phoronix.com/news/Broadcom-V3D-Some-Deprecations
- Source link:
Broadcom V3D 3.3 and V3D 4.1 graphics IP is set to be deprecated and removed from the V3D kernel graphics/display driver after the Mesa driver support was removed two years ago already. The situation in both cases amount to lack of hardware by developers for testing and with that likely no other known users of these particular Broadcom graphics in selects SoCs.
The Broadcom V3D 3.3 graphics is found in the BCM7268 SoC and the V3D 4.1 graphics is found with the Broadcom BCM7278. The BCM7268 was [1]the first SoC with their VideoCore V "VC5" IP but doesn't look like this SoC ever found any widespread deployments with limited information on it online. The BCM7278 looks like it was only ever found in a few set-top box devices and again a rare find, especially with anyone would that would be running a mainline Linux kernel off it.
Maíra Canal of Igalia sent out the patch on Saturday to deprecate the V3D 3.3 and V3D 4.1 IP from the Broadcom V3D kernel driver. Maíra commented on that patch:
"V3D 3.3 (Broadcom BCM7268) and V3D 4.1 (Broadcom BCM7278) has had no in-tree userspace since Mesa dropped support in 2024, on the grounds that those generations were no longer being tested. The situation in the kernel is similar: the maintainers don't have this hardware, the hardware is not available for purchase, and there is no known user of these GPUs.
With no userspace left to drive it and no known users, maintaining the ver <= 41 code paths is a cost without a benefit, considering that these paths are not being exercised on real hardware.
As a first step toward removal, emit a deprecation warning at probe for V3D versions earlier than or equal to 4.1. The hardware remains functional for now; this only warns. If any real user appears and explain its use-case, support can be retained.
Schedule the removal of V3D 3.3 and 4.1 support to the next kernel release."
If this patch lands in time for the upcoming Linux v7.2 cycle, it could then lead to the support being stripped out in Linux v7.3 later in the year.
[1] https://www.phoronix.com/news/BCM7268-DRM-Work-Begins
The Broadcom V3D 3.3 graphics is found in the BCM7268 SoC and the V3D 4.1 graphics is found with the Broadcom BCM7278. The BCM7268 was [1]the first SoC with their VideoCore V "VC5" IP but doesn't look like this SoC ever found any widespread deployments with limited information on it online. The BCM7278 looks like it was only ever found in a few set-top box devices and again a rare find, especially with anyone would that would be running a mainline Linux kernel off it.
Maíra Canal of Igalia sent out the patch on Saturday to deprecate the V3D 3.3 and V3D 4.1 IP from the Broadcom V3D kernel driver. Maíra commented on that patch:
"V3D 3.3 (Broadcom BCM7268) and V3D 4.1 (Broadcom BCM7278) has had no in-tree userspace since Mesa dropped support in 2024, on the grounds that those generations were no longer being tested. The situation in the kernel is similar: the maintainers don't have this hardware, the hardware is not available for purchase, and there is no known user of these GPUs.
With no userspace left to drive it and no known users, maintaining the ver <= 41 code paths is a cost without a benefit, considering that these paths are not being exercised on real hardware.
As a first step toward removal, emit a deprecation warning at probe for V3D versions earlier than or equal to 4.1. The hardware remains functional for now; this only warns. If any real user appears and explain its use-case, support can be retained.
Schedule the removal of V3D 3.3 and 4.1 support to the next kernel release."
If this patch lands in time for the upcoming Linux v7.2 cycle, it could then lead to the support being stripped out in Linux v7.3 later in the year.
[1] https://www.phoronix.com/news/BCM7268-DRM-Work-Begins