Re: [PATCH 1/7] drm/msm/dp: Replace open-coded drm_dp_read_dpcd_caps()

From: Kuogee Hsieh
Date: Thu Aug 31 2023 - 16:27:41 EST



On 8/29/2023 11:47 AM, Stephen Boyd wrote:
This function duplicates the common function drm_dp_read_dpcd_caps().
The array of DPCD registers filled in is one size larger than the
function takes, but from what I can tell that extra byte was never used.
Resize the array and use the common function to reduce the code here.

Cc: Vinod Polimera <quic_vpolimer@xxxxxxxxxxx>
Cc: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
Tested-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
Reviewed-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
---
drivers/gpu/drm/msm/dp/dp_panel.c | 42 ++++---------------------------
drivers/gpu/drm/msm/dp/dp_panel.h | 4 +--
2 files changed, 6 insertions(+), 40 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/msm/dp/dp_panel.c
index 42d52510ffd4..09d4f6c38ef8 100644
--- a/drivers/gpu/drm/msm/dp/dp_panel.c
+++ b/drivers/gpu/drm/msm/dp/dp_panel.c
@@ -48,47 +48,15 @@ static int dp_panel_read_dpcd(struct dp_panel *dp_panel)
ssize_t rlen;
struct dp_panel_private *panel;
struct dp_link_info *link_info;
- u8 *dpcd, major = 0, minor = 0, temp;
- u32 offset = DP_DPCD_REV;
+ u8 *dpcd, major, minor;
+ panel = container_of(dp_panel, struct dp_panel_private, dp_panel);
dpcd = dp_panel->dpcd;
+ rc = drm_dp_read_dpcd_caps(panel->aux, dpcd);
+ if (rc)
+ return rc;
- panel = container_of(dp_panel, struct dp_panel_private, dp_panel);
link_info = &dp_panel->link_info;
-
- rlen = drm_dp_dpcd_read(panel->aux, offset,
- dpcd, (DP_RECEIVER_CAP_SIZE + 1));
- if (rlen < (DP_RECEIVER_CAP_SIZE + 1)) {
- DRM_ERROR("dpcd read failed, rlen=%zd\n", rlen);
- if (rlen == -ETIMEDOUT)
- rc = rlen;
- else
- rc = -EINVAL;
-
- goto end;
- }
-
- temp = dpcd[DP_TRAINING_AUX_RD_INTERVAL];
-
- /* check for EXTENDED_RECEIVER_CAPABILITY_FIELD_PRESENT */
- if (temp & BIT(7)) {
- drm_dbg_dp(panel->drm_dev,
- "using EXTENDED_RECEIVER_CAPABILITY_FIELD\n");
- offset = DPRX_EXTENDED_DPCD_FIELD;
- }
-
- rlen = drm_dp_dpcd_read(panel->aux, offset,
- dpcd, (DP_RECEIVER_CAP_SIZE + 1));
- if (rlen < (DP_RECEIVER_CAP_SIZE + 1)) {
- DRM_ERROR("dpcd read failed, rlen=%zd\n", rlen);
- if (rlen == -ETIMEDOUT)
- rc = rlen;
- else
- rc = -EINVAL;
-
- goto end;
- }
-
link_info->revision = dpcd[DP_DPCD_REV];
major = (link_info->revision >> 4) & 0x0f;
minor = link_info->revision & 0x0f;
diff --git a/drivers/gpu/drm/msm/dp/dp_panel.h b/drivers/gpu/drm/msm/dp/dp_panel.h
index ed1030e17e1b..6d733480a62d 100644
--- a/drivers/gpu/drm/msm/dp/dp_panel.h
+++ b/drivers/gpu/drm/msm/dp/dp_panel.h
@@ -13,8 +13,6 @@
struct edid;
-#define DPRX_EXTENDED_DPCD_FIELD 0x2200
-
#define DP_DOWNSTREAM_PORTS 4
#define DP_DOWNSTREAM_CAP_SIZE 4
@@ -40,7 +38,7 @@ struct dp_panel_psr {
struct dp_panel {
/* dpcd raw data */
- u8 dpcd[DP_RECEIVER_CAP_SIZE + 1];
+ u8 dpcd[DP_RECEIVER_CAP_SIZE];
u8 ds_cap_info[DP_DOWNSTREAM_PORTS * DP_DOWNSTREAM_CAP_SIZE];
u32 ds_port_cnt;
u32 dfp_present;