From: Marijn Suijten <marijn.suijten@somainline.org>
To: phone-devel@vger.kernel.org
Cc: ~postmarketos/upstreaming@lists.sr.ht,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@somainline.org>,
Konrad Dybcio <konrad.dybcio@somainline.org>,
Martin Botka <martin.botka@somainline.org>,
Jami Kettunen <jami.kettunen@somainline.org>,
Marijn Suijten <marijn.suijten@somainline.org>,
Rob Clark <robdclark@gmail.com>,
Abhinav Kumar <quic_abhinavk@quicinc.com>,
Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
Sean Paul <sean@poorly.run>, David Airlie <airlied@gmail.com>,
Daniel Vetter <daniel@ffwll.ch>, Vinod Koul <vkoul@kernel.org>,
Douglas Anderson <dianders@chromium.org>,
Vladimir Lypak <vladimir.lypak@gmail.com>,
linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3 10/10] drm/msm/dsi: Prevent signed BPG offsets from bleeding into adjacent bits
Date: Sun, 9 Oct 2022 20:53:15 +0200 [thread overview]
Message-ID: <20221009185316.462522-3-marijn.suijten@somainline.org> (raw)
In-Reply-To: <20221009184824.457416-1-marijn.suijten@somainline.org>
The bpg_offset array contains negative BPG offsets which fill the full 8
bits of a char thanks to two's complement: this however results in those
bits bleeding into the next field when the value is packed into DSC PPS
by the drm_dsc_helper function, which only expects range_bpg_offset to
contain 6-bit wide values. As a consequence random slices appear
corrupted on-screen (tested on a Sony Tama Akatsuki device with sdm845).
Use AND operators to limit these two's complement values to 6 bits,
similar to the AMD and i915 drivers.
Fixes: b9080324d6ca ("drm/msm/dsi: add support for dsc data")
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
---
drivers/gpu/drm/msm/dsi/dsi_host.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 46032c576a59..c5c2d70ac27d 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -1804,7 +1804,11 @@ static int dsi_populate_dsc_params(struct msm_dsi_host *msm_host, struct drm_dsc
for (i = 0; i < DSC_NUM_BUF_RANGES; i++) {
dsc->rc_range_params[i].range_min_qp = min_qp[i];
dsc->rc_range_params[i].range_max_qp = max_qp[i];
- dsc->rc_range_params[i].range_bpg_offset = bpg_offset[i];
+ /*
+ * Range BPG Offset contains two's-complement signed values that fill
+ * 8 bits, yet the registers and DCS PPS field are only 6 bits wide.
+ */
+ dsc->rc_range_params[i].range_bpg_offset = bpg_offset[i] & DSC_RANGE_BPG_OFFSET_MASK;
}
dsc->initial_offset = 6144; /* Not bpp 12 */
--
2.38.0
next prev parent reply other threads:[~2022-10-09 18:53 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-09 18:48 [PATCH v3 00/10] drm/msm: Fix math issues in MSM DSC implementation Marijn Suijten
2022-10-09 18:48 ` [PATCH v3 01/10] drm/msm/dsi: Remove useless math in DSC calculations Marijn Suijten
2022-10-09 18:52 ` Dmitry Baryshkov
2022-10-09 18:48 ` [PATCH v3 02/10] drm/msm/dsi: Remove repeated calculation of slice_per_intf Marijn Suijten
2022-10-09 18:53 ` Dmitry Baryshkov
2022-10-09 18:48 ` [PATCH v3 03/10] drm/msm/dsi: Use DIV_ROUND_UP instead of conditional increment on modulo Marijn Suijten
2022-10-09 18:53 ` Dmitry Baryshkov
2022-10-09 18:48 ` [PATCH v3 04/10] drm/msm/dsi: Reuse earlier computed dsc->slice_chunk_size Marijn Suijten
2022-10-09 18:54 ` Dmitry Baryshkov
2022-10-09 18:48 ` [PATCH v3 05/10] drm/msm/dsi: Appropriately set dsc->mux_word_size based on bpc Marijn Suijten
2022-10-09 18:55 ` Dmitry Baryshkov
2022-10-12 22:53 ` Abhinav Kumar
2022-10-09 18:48 ` [PATCH v3 06/10] drm/msm/dsi: Migrate to drm_dsc_compute_rc_parameters() Marijn Suijten
2022-10-09 18:56 ` Dmitry Baryshkov
2022-10-09 18:50 ` Marijn Suijten
2022-10-09 18:58 ` Marijn Suijten
2022-10-12 23:03 ` [Freedreno] " Abhinav Kumar
2022-10-13 9:36 ` Marijn Suijten
2022-10-13 16:02 ` Abhinav Kumar
2022-10-17 8:59 ` Marijn Suijten
2022-10-17 13:37 ` Caleb Connolly
2022-10-17 16:28 ` Abhinav Kumar
2022-10-09 18:51 ` [PATCH v3 07/10] drm/msm/dsi: Disallow 8 BPC DSC configuration for alternative BPC values Marijn Suijten
2022-10-09 18:57 ` Dmitry Baryshkov
2022-10-09 23:53 ` kernel test robot
2022-10-12 23:08 ` Abhinav Kumar
2022-10-13 9:27 ` Marijn Suijten
2022-10-09 18:53 ` [PATCH v3 08/10] drm/msm/dsi: Account for DSC's bits_per_pixel having 4 fractional bits Marijn Suijten
2022-10-09 19:24 ` Dmitry Baryshkov
2022-10-12 23:25 ` Abhinav Kumar
2022-10-09 18:53 ` [PATCH v3 09/10] drm/msm/dpu1: " Marijn Suijten
2022-10-09 18:53 ` Marijn Suijten [this message]
2022-10-09 19:14 ` [PATCH v3 10/10] drm/msm/dsi: Prevent signed BPG offsets from bleeding into adjacent bits Dmitry Baryshkov
2022-10-11 7:51 ` Marijn Suijten
2022-10-12 23:26 ` Abhinav Kumar
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