[PATCH v2 0/2] soundwire: Remove redundant zeroing of page registers

Richard Fitzgerald posted 2 patches 2 years, 7 months ago
drivers/soundwire/bus.c             | 23 -----------------------
drivers/soundwire/cadence_master.c  | 14 --------------
drivers/soundwire/cadence_master.h  |  3 ---
drivers/soundwire/intel_auxdevice.c |  1 -
include/linux/soundwire/sdw.h       |  3 ---
5 files changed, 44 deletions(-)
[PATCH v2 0/2] soundwire: Remove redundant zeroing of page registers
Posted by Richard Fitzgerald 2 years, 7 months ago
Writing zero to the page registers after each message transaction can add
up to a lot of overhead for codecs that need to transfer large amount of
data - for example a firmware download.

There's no spec reason I can see for this zeroing. The page registers are
only used for a paged address. The bus code uses a non-paged address for
registers in page 0. It always writes the page registers at the start of
a paged transaction.

If this zeroing was a workaround for anything, let me know and I will
re-implement the zeroing as a quirk that can be enabled only when it is
necessary.

Changes since v1:
- Reworded the commit message to patch #1:
  - say that this is for devices that support paging
  - mention bit 15 as the paging flag
  - split a long sentence into two sentences.

No code changes.

Richard Fitzgerald (2):
  soundwire: bus: Don't zero page registers after every transaction
  soundwire: bus: Remove unused reset_page_addr() callback

 drivers/soundwire/bus.c             | 23 -----------------------
 drivers/soundwire/cadence_master.c  | 14 --------------
 drivers/soundwire/cadence_master.h  |  3 ---
 drivers/soundwire/intel_auxdevice.c |  1 -
 include/linux/soundwire/sdw.h       |  3 ---
 5 files changed, 44 deletions(-)

-- 
2.30.2
Re: [PATCH v2 0/2] soundwire: Remove redundant zeroing of page registers
Posted by Vinod Koul 2 years, 7 months ago
On 23-01-23, 16:49, Richard Fitzgerald wrote:
> Writing zero to the page registers after each message transaction can add
> up to a lot of overhead for codecs that need to transfer large amount of
> data - for example a firmware download.
> 
> There's no spec reason I can see for this zeroing. The page registers are
> only used for a paged address. The bus code uses a non-paged address for
> registers in page 0. It always writes the page registers at the start of
> a paged transaction.
> 
> If this zeroing was a workaround for anything, let me know and I will
> re-implement the zeroing as a quirk that can be enabled only when it is
> necessary.

Applied, thanks

-- 
~Vinod