Re: [PATCH AUTOSEL 5.10 14/36] media: rkisp1: uapi: change hist_bins array type from __u16 to __u32

From: Dafna Hirschfeld
Date: Tue Feb 09 2021 - 07:47:48 EST




Am 08.02.21 um 21:46 schrieb Hans Verkuil:
On 08/02/2021 18:57, Sasha Levin wrote:
From: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>

[ Upstream commit 31f190e0ccac8b75d33fdc95a797c526cf9b149e ]

Each entry in the array is a 20 bits value composed of 16 bits unsigned
integer and 4 bits fractional part. So the type should change to __u32.
In addition add a documentation of how the measurements are done.

Dafna, Helen, does it make sense at all to backport these three patches to
when rkisp1 was a staging driver?

I would be inclined not to backport this.

I also don't think it makes sense since this changes the uapi and it is not really a bug fix.


Thanks,
Dafna


Regards,

Hans


Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
Acked-by: Helen Koike <helen.koike@xxxxxxxxxxxxx>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/staging/media/rkisp1/uapi/rkisp1-config.h | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/media/rkisp1/uapi/rkisp1-config.h b/drivers/staging/media/rkisp1/uapi/rkisp1-config.h
index 432cb6be55b47..c19fe059c2442 100644
--- a/drivers/staging/media/rkisp1/uapi/rkisp1-config.h
+++ b/drivers/staging/media/rkisp1/uapi/rkisp1-config.h
@@ -848,13 +848,18 @@ struct rkisp1_cif_isp_af_stat {
/**
* struct rkisp1_cif_isp_hist_stat - statistics histogram data
*
- * @hist_bins: measured bin counters
+ * @hist_bins: measured bin counters. Each bin is a 20 bits unsigned fixed point
+ * type. Bits 0-4 are the fractional part and bits 5-19 are the
+ * integer part.
*
- * Measurement window divided into 25 sub-windows, set
- * with ISP_HIST_XXX
+ * The window of the measurements area is divided to 5x5 sub-windows. The
+ * histogram is then computed for each sub-window independently and the final
+ * result is a weighted average of the histogram measurements on all
+ * sub-windows. The window of the measurements area and the weight of each
+ * sub-window are configurable using struct @rkisp1_cif_isp_hst_config.
*/
struct rkisp1_cif_isp_hist_stat {
- __u16 hist_bins[RKISP1_CIF_ISP_HIST_BIN_N_MAX];
+ __u32 hist_bins[RKISP1_CIF_ISP_HIST_BIN_N_MAX];
};
/**