On 04/04/2023 19:29, Jessica Zhang wrote:
On 4/3/2023 5:33 PM, Dmitry Baryshkov wrote:
On 04/04/2023 00:38, Jessica Zhang wrote:
On 4/2/2023 4:21 AM, Dmitry Baryshkov wrote:
On 31/03/2023 21:49, Jessica Zhang wrote:
Introduce MSM-specific DSC helper methods, as some calculations are
common between DP and DSC.
Changes in v2:
- Moved files up to msm/ directory
- Dropped get_comp_ratio() helper
- Used drm_int2fixp() to convert to integers to fp
- Style changes to improve readability
- Dropped unused bpp variable in msm_dsc_get_dce_bytes_per_line()
- Changed msm_dsc_get_slice_per_intf() to a static inline method
- Dropped last division step of msm_dsc_get_pclk_per_line() and
changed
method name accordingly
- Changed DSC_BPP macro to drm_dsc_get_bpp_int() helper method
- Fixed some math issues caused by passing in incorrect types to
drm_fixed methods in get_bytes_per_soft_slice()
Signed-off-by: Jessica Zhang <quic_jesszhan@xxxxxxxxxxx>
---
drivers/gpu/drm/msm/Makefile | 1 +
drivers/gpu/drm/msm/msm_dsc_helper.c | 53
++++++++++++++++++++++++++++++++++++
drivers/gpu/drm/msm/msm_dsc_helper.h | 42
++++++++++++++++++++++++++++
3 files changed, 96 insertions(+)
diff --git a/drivers/gpu/drm/msm/Makefile
b/drivers/gpu/drm/msm/Makefile
index 7274c41228ed..b814fc80e2d5 100644
--- a/drivers/gpu/drm/msm/Makefile
+++ b/drivers/gpu/drm/msm/Makefile
@@ -94,6 +94,7 @@ msm-y += \
msm_atomic_tracepoints.o \
msm_debugfs.o \
msm_drv.o \
+ msm_dsc_helper.o \
msm_fb.o \
msm_fence.o \
msm_gem.o \
diff --git a/drivers/gpu/drm/msm/msm_dsc_helper.c
b/drivers/gpu/drm/msm/msm_dsc_helper.c
new file mode 100644
index 000000000000..60b73e17e6eb
--- /dev/null
+++ b/drivers/gpu/drm/msm/msm_dsc_helper.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights
reserved
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <drm/drm_fixed.h>
+
+#include "msm_drv.h"
+#include "msm_dsc_helper.h"
+
+static s64 get_bytes_per_soft_slice(struct drm_dsc_config *dsc,
int intf_width, u32 src_bpp)
intf_width is unused
Hi Dmitry,
Acked.
+{
+ int bpp = msm_dsc_get_bpp_int(dsc);
+ s64 numerator_fp, denominator_fp;
+ s64 comp_ratio_fp = drm_fixp_from_fraction(src_bpp, bpp);
+
+ numerator_fp = drm_int2fixp(dsc->slice_width * 3);
You have lost dsc->bits_per_component here.
This was moved to the denominator calculation, but I'll move it back
to this line to avoid confusion.
Maybe you occasionally mixed bpp and bpc, because there is no
bits_per_component usage in denominator. Could you please recheck the
calculations.
+ denominator_fp = drm_fixp_from_fraction(comp_ratio_fp * 8,
drm_int2fixp(bpp));
denominator_fp = drm_fixp_from_fraction(src_bpp * 8, bpp);
Acked.
+
+ return drm_fixp_div(numerator_fp, denominator_fp);
+}
+
+u32 msm_dsc_get_eol_byte_num(struct drm_dsc_config *dsc, int
intf_width, u32 src_bpp)
+{
+ u32 bytes_per_soft_slice, extra_eol_bytes, bytes_per_intf;
+ s64 bytes_per_soft_slice_fp;
+ int slice_per_intf = msm_dsc_get_slice_per_intf(dsc, intf_width);
+
+ bytes_per_soft_slice_fp = get_bytes_per_soft_slice(dsc,
intf_width, src_bpp);
+ bytes_per_soft_slice =
drm_fixp2int_ceil(bytes_per_soft_slice_fp);
+
+ bytes_per_intf = bytes_per_soft_slice * slice_per_intf;
+ extra_eol_bytes = bytes_per_intf % 3;
+ if (extra_eol_bytes != 0)
+ extra_eol_bytes = 3 - extra_eol_bytes;
I become confused here when I checked eol_bytes in the display
techpack.
I see that for DP the dp_panel_dsc_pclk_param_calc() calculates
dsc->eol_bytes_num in this way, the size to pad dsc_byte_count *
slice_per_intf to 3 bytes.
However, for DSI this is a simple as total_bytes_per_intf % 3 , so
it is not a padding, but a length of the last chunk.
Could you please clarify? If the techpack code is correct, I'd
prefer if we return last chunk size here and calculate the padding
length in the DP driver.
I've double checked the calculations between DP and DSI, and I think
you're right. Will move the `if (extra_eol_bytes != 0)` block out to
DP code.
Ack. Could you please check with HW team that our understanding is
correct?
Hey Dmitry,
I've checked with the HW team and looks like the math for eol_byte_nums
differs between DP and DSI.
For DSI, eol_byte_num = bytes_per_intf % 3
But for DP, eol_byte_num = (bytes_per_intf % 3 == 0) ? 0 : 3 -
bytes_per_intf % 3 *only* for non-widebus.
For DP && widebus enabled, eol_byte_num = (bytes_per_intf % 6 == 0) ? 0
: 6 - bytes_per_intf % 6
In that case, we should move even the bytes_per_intf % 3 out and change
this method to msm_dsc_get_bytes_per_intf() instead.
Thanks for the note. I'm looking forward to seeing the v3 then.
Thanks,
Jessica Zhang
--
With best wishes
Dmitry
