linux-kernel - Re: [PATCH v4 03/11] drm/bridge: it6505: add aux operation for HDCP ksv list read

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Message-ID: <CAA8EJppErpCagvTQ4TTnBvUbAFci=BvMEmoeOxT1YmPdOPwu-w@mail.gmail.com>
Date: Thu, 26 Sep 2024 14:17:13 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Hermes.Wu@....com.tw
Cc: Kenneth.Hung@....com.tw, andrzej.hajda@...el.com, 
	neil.armstrong@...aro.org, rfoss@...nel.org, 
	Laurent.pinchart@...asonboard.com, jonas@...boo.se, jernej.skrabec@...il.com, 
	maarten.lankhorst@...ux.intel.com, mripard@...nel.org, tzimmermann@...e.de, 
	airlied@...il.com, simona@...ll.ch, angelogioacchino.delregno@...labora.com, 
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 03/11] drm/bridge: it6505: add aux operation for HDCP
 ksv list read

On Thu, 26 Sept 2024 at 11:46, <Hermes.Wu@....com.tw> wrote:
>
> >On Thu, Sep 26, 2024 at 03:47:53PM GMT, Hermes Wu wrote:
> >> From: Hermes Wu <Hermes.wu@....com.tw>
> >>
> >> Add aux operaction command which supports read DPCD KSV FIFO with aux
> >> fifo.
> >
> >Nit: AUX, FIFO. Please be consistent in your commit messages.
> >
> >>
> >>
> >> Fixes: b5c84a9edcd4 ("drm/bridge: add it6505 driver")
> >
> >Why is this considered to be a fix? From the commit message it sounds like a new feature.
>
> It will be a necessary change for HDCP reads KSV FIFO.

First of all, it should be a part of the commit message, because the
patch itself doesn't fix an issue.
Judging by the amount and the intrusivity of the patches, I'd say that
all KSV / HDCP-related patches constitute a new development, rather
than a bugfix.

>
>
> >
> >LGTM otherwise
> >
> >> Signed-off-by: Hermes Wu <Hermes.wu@....com.tw>
> >> ---
> >>  drivers/gpu/drm/bridge/ite-it6505.c | 12 ++++++++----
> >>  1 file changed, 8 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/bridge/ite-it6505.c
> >> b/drivers/gpu/drm/bridge/ite-it6505.c
> >> index b451d3c2ac1d..0583abdca75f 100644
> >> --- a/drivers/gpu/drm/bridge/ite-it6505.c
> >> +++ b/drivers/gpu/drm/bridge/ite-it6505.c
> >> @@ -324,6 +324,9 @@ enum aux_cmd_type {
> >>      CMD_AUX_NATIVE_READ = 0x0,
> >>      CMD_AUX_NATIVE_WRITE = 0x5,
> >>      CMD_AUX_I2C_EDID_READ = 0xB,
> >> +
> >> +    /* KSV list read using AUX native read with FIFO */
> >> +    CMD_AUX_GET_KSV_LIST = 0x10,
> >>  };
> >>
> >>  enum aux_cmd_reply {
> >> @@ -965,7 +968,8 @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
> >>      it6505_set_bits(it6505, REG_AUX_CTRL, AUX_USER_MODE, AUX_USER_MODE);
> >>
> >>  aux_op_start:
> >> -    if (cmd == CMD_AUX_I2C_EDID_READ) {
> >> +    /* HW AUX FIFO supports only EDID and DCPD KSV FIFO aread */
> >> +    if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
> >>              /* AUX EDID FIFO has max length of AUX_FIFO_MAX_SIZE bytes. */
> >>              size = min_t(size_t, size, AUX_FIFO_MAX_SIZE);
> >>              /* Enable AUX FIFO read back and clear FIFO */ @@ -1030,7 +1034,7
> >> @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
> >>              goto aux_op_start;
> >>      }
> >>
> >> -    if (cmd == CMD_AUX_I2C_EDID_READ) {
> >> +    if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
> >>              for (i = 0; i < size; i++) {
> >>                      ret = it6505_read(it6505, REG_AUX_DATA_FIFO);
> >>                      if (ret < 0)
> >> @@ -1055,7 +1059,7 @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
> >>      ret = i;
> >>
> >>  aux_op_err:
> >> -    if (cmd == CMD_AUX_I2C_EDID_READ) {
> >> +    if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
> >>              /* clear AUX FIFO */
> >>              it6505_set_bits(it6505, REG_AUX_CTRL,
> >>                              AUX_EN_FIFO_READ | CLR_EDID_FIFO, @@ -1079,7 +1083,7 @@ static
> >> ssize_t it6505_aux_do_transfer(struct it6505 *it6505,
> >>
> >>      mutex_lock(&it6505->aux_lock);
> >>      for (i = 0; i < size; ) {
> >> -            if (cmd == CMD_AUX_I2C_EDID_READ)
> >> +            if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST)
> >>                      request_size = min_t(int, (int)size - i, AUX_FIFO_MAX_SIZE);
> >>              else
> >>                      request_size = min_t(int, (int)size - i, 4);
> >> --
> >> 2.34.1
> >>
> >
> >--
> >With best wishes
> >Dmitry
> >
>
> BR,
> Hermes
>


-- 
With best wishes
Dmitry