diff mbox series

[v6,03/10] drm/bridge: it6505: add AUX operation for HDCP KSV list read

Message ID 20241016-upstream-v6-v6-3-4d93a0c46de1@ite.com.tw (mailing list archive)
State New, archived
Headers show
Series drm/bridge: it6505: fix HDCP CTS fail items and add MCCS support | expand

Commit Message

Hermes Wu via B4 Relay Oct. 16, 2024, 7:54 a.m. UTC 
From: Hermes Wu <Hermes.wu@ite.com.tw>

HDCP KSV list readback can choose to use AUX FIFO or
general data register.
For some DisplayPort devices, the KSV list must be read
in 5 byte boundaries.
The original AUX read command does not support these devices.

The AUX command operation control register "REG_AUX_CMD_REQ" uses b[3:0]
as AUX operacion control, and b[7:4] are status bits and read only.
To change KSV read operation uses "CMD_AUX_NATIVE_READ" from using
the data registers to using AUX FIFO.
The extended command "CMD_AUX_GET_KSV_LIST" is added as
"CMD_AUX_NATIVE_READ" with the 0x10 flag which selects AUX FIFO mode.

Signed-off-by: Hermes Wu <Hermes.wu@ite.com.tw>
---
 drivers/gpu/drm/bridge/ite-it6505.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

Comments

kernel test robot Oct. 19, 2024, 11:30 p.m. UTC | #1 
Hi Hermes,

kernel test robot noticed the following build errors:

[auto build test ERROR on b8128f7815ff135f0333c1b46dcdf1543c41b860]

url:    https://github.com/intel-lab-lkp/linux/commits/Hermes-Wu-via-B4-Relay/drm-bridge-it6505-Change-definition-of-AUX_FIFO_MAX_SIZE/20241016-155607
base:   b8128f7815ff135f0333c1b46dcdf1543c41b860
patch link:    https://lore.kernel.org/r/20241016-upstream-v6-v6-3-4d93a0c46de1%40ite.com.tw
patch subject: [PATCH v6 03/10] drm/bridge: it6505: add AUX operation for HDCP KSV list read
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20241020/202410200756.KlsPLE8A-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project bfe84f7085d82d06d61c632a7bad1e692fd159e4)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241020/202410200756.KlsPLE8A-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410200756.KlsPLE8A-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from drivers/gpu/drm/bridge/ite-it6505.c:13:
   In file included from include/linux/i2c.h:19:
   In file included from include/linux/regulator/consumer.h:35:
   In file included from include/linux/suspend.h:5:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:8:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:548:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     548 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:561:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     561 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from drivers/gpu/drm/bridge/ite-it6505.c:13:
   In file included from include/linux/i2c.h:19:
   In file included from include/linux/regulator/consumer.h:35:
   In file included from include/linux/suspend.h:5:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:8:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:574:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     574 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from drivers/gpu/drm/bridge/ite-it6505.c:13:
   In file included from include/linux/i2c.h:19:
   In file included from include/linux/regulator/consumer.h:35:
   In file included from include/linux/suspend.h:5:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:8:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:585:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     585 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:595:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     595 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:605:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     605 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   In file included from drivers/gpu/drm/bridge/ite-it6505.c:13:
   In file included from include/linux/i2c.h:19:
   In file included from include/linux/regulator/consumer.h:35:
   In file included from include/linux/suspend.h:5:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:21:
   In file included from include/linux/mm.h:2213:
   include/linux/vmstat.h:518:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     518 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
>> drivers/gpu/drm/bridge/ite-it6505.c:1004:40: error: call to undeclared function 'FIELD_GET'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1004 |         it6505_write(it6505, REG_AUX_CMD_REQ, FIELD_GET(M_AUX_REQ_CMD, cmd));
         |                                               ^
   7 warnings and 1 error generated.

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for MODVERSIONS
   Depends on [n]: MODULES [=y] && !COMPILE_TEST [=y]
   Selected by [y]:
   - RANDSTRUCT_FULL [=y] && (CC_HAS_RANDSTRUCT [=y] || GCC_PLUGINS [=n]) && MODULES [=y]
   WARNING: unmet direct dependencies detected for GET_FREE_REGION
   Depends on [n]: SPARSEMEM [=n]
   Selected by [m]:
   - RESOURCE_KUNIT_TEST [=m] && RUNTIME_TESTING_MENU [=y] && KUNIT [=m]


vim +/FIELD_GET +1004 drivers/gpu/drm/bridge/ite-it6505.c

   956	
   957	static ssize_t it6505_aux_operation(struct it6505 *it6505,
   958					    enum aux_cmd_type cmd,
   959					    unsigned int address, u8 *buffer,
   960					    size_t size, enum aux_cmd_reply *reply)
   961	{
   962		int i, ret;
   963		bool aux_write_check = false;
   964	
   965		if (!it6505_get_sink_hpd_status(it6505))
   966			return -EIO;
   967	
   968		/* set AUX user mode */
   969		it6505_set_bits(it6505, REG_AUX_CTRL, AUX_USER_MODE, AUX_USER_MODE);
   970	
   971	aux_op_start:
   972		/* HW AUX FIFO supports only EDID and DCPD KSV FIFO area */
   973		if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
   974			/* AUX EDID FIFO has max length of AUX_FIFO_MAX_SIZE bytes. */
   975			size = min_t(size_t, size, AUX_FIFO_MAX_SIZE);
   976			/* Enable AUX FIFO read back and clear FIFO */
   977			it6505_set_bits(it6505, REG_AUX_CTRL,
   978					AUX_EN_FIFO_READ | CLR_EDID_FIFO,
   979					AUX_EN_FIFO_READ | CLR_EDID_FIFO);
   980	
   981			it6505_set_bits(it6505, REG_AUX_CTRL,
   982					AUX_EN_FIFO_READ | CLR_EDID_FIFO,
   983					AUX_EN_FIFO_READ);
   984		} else {
   985			/* The DP AUX transmit buffer has 4 bytes. */
   986			size = min_t(size_t, size, 4);
   987			it6505_set_bits(it6505, REG_AUX_CTRL, AUX_NO_SEGMENT_WR,
   988					AUX_NO_SEGMENT_WR);
   989		}
   990	
   991		/* Start Address[7:0] */
   992		it6505_write(it6505, REG_AUX_ADR_0_7, (address >> 0) & 0xFF);
   993		/* Start Address[15:8] */
   994		it6505_write(it6505, REG_AUX_ADR_8_15, (address >> 8) & 0xFF);
   995		/* WriteNum[3:0]+StartAdr[19:16] */
   996		it6505_write(it6505, REG_AUX_ADR_16_19,
   997			     ((address >> 16) & 0x0F) | ((size - 1) << 4));
   998	
   999		if (cmd == CMD_AUX_NATIVE_WRITE)
  1000			regmap_bulk_write(it6505->regmap, REG_AUX_OUT_DATA0, buffer,
  1001					  size);
  1002	
  1003		/* Aux Fire */
> 1004		it6505_write(it6505, REG_AUX_CMD_REQ, FIELD_GET(M_AUX_REQ_CMD, cmd));
  1005	
  1006		ret = it6505_aux_wait(it6505);
  1007		if (ret < 0)
  1008			goto aux_op_err;
  1009	
  1010		ret = it6505_read(it6505, REG_AUX_ERROR_STS);
  1011		if (ret < 0)
  1012			goto aux_op_err;
  1013	
  1014		switch ((ret >> 6) & 0x3) {
  1015		case 0:
  1016			*reply = REPLY_ACK;
  1017			break;
  1018		case 1:
  1019			*reply = REPLY_DEFER;
  1020			ret = -EAGAIN;
  1021			goto aux_op_err;
  1022		case 2:
  1023			*reply = REPLY_NACK;
  1024			ret = -EIO;
  1025			goto aux_op_err;
  1026		case 3:
  1027			ret = -ETIMEDOUT;
  1028			goto aux_op_err;
  1029		}
  1030	
  1031		/* Read back Native Write data */
  1032		if (cmd == CMD_AUX_NATIVE_WRITE) {
  1033			aux_write_check = true;
  1034			cmd = CMD_AUX_NATIVE_READ;
  1035			goto aux_op_start;
  1036		}
  1037	
  1038		if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
  1039			for (i = 0; i < size; i++) {
  1040				ret = it6505_read(it6505, REG_AUX_DATA_FIFO);
  1041				if (ret < 0)
  1042					goto aux_op_err;
  1043				buffer[i] = ret;
  1044			}
  1045		} else {
  1046			for (i = 0; i < size; i++) {
  1047				ret = it6505_read(it6505, REG_AUX_DATA_0_7 + i);
  1048				if (ret < 0)
  1049					goto aux_op_err;
  1050	
  1051				if (aux_write_check && buffer[size - 1 - i] != ret) {
  1052					ret = -EINVAL;
  1053					goto aux_op_err;
  1054				}
  1055	
  1056				buffer[size - 1 - i] = ret;
  1057			}
  1058		}
  1059	
  1060		ret = i;
  1061	
  1062	aux_op_err:
  1063		if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
  1064			/* clear AUX FIFO */
  1065			it6505_set_bits(it6505, REG_AUX_CTRL,
  1066					AUX_EN_FIFO_READ | CLR_EDID_FIFO,
  1067					AUX_EN_FIFO_READ | CLR_EDID_FIFO);
  1068			it6505_set_bits(it6505, REG_AUX_CTRL,
  1069					AUX_EN_FIFO_READ | CLR_EDID_FIFO, 0x00);
  1070		}
  1071	
  1072		/* Leave AUX user mode */
  1073		it6505_set_bits(it6505, REG_AUX_CTRL, AUX_USER_MODE, 0);
  1074	
  1075		return ret;
  1076	}
  1077
kernel test robot Oct. 20, 2024, 12:52 a.m. UTC | #2 
Hi Hermes,

kernel test robot noticed the following build errors:

[auto build test ERROR on b8128f7815ff135f0333c1b46dcdf1543c41b860]

url:    https://github.com/intel-lab-lkp/linux/commits/Hermes-Wu-via-B4-Relay/drm-bridge-it6505-Change-definition-of-AUX_FIFO_MAX_SIZE/20241016-155607
base:   b8128f7815ff135f0333c1b46dcdf1543c41b860
patch link:    https://lore.kernel.org/r/20241016-upstream-v6-v6-3-4d93a0c46de1%40ite.com.tw
patch subject: [PATCH v6 03/10] drm/bridge: it6505: add AUX operation for HDCP KSV list read
config: m68k-allmodconfig (https://download.01.org/0day-ci/archive/20241020/202410200624.sr8sF1ya-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 14.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241020/202410200624.sr8sF1ya-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410200624.sr8sF1ya-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/gpu/drm/bridge/ite-it6505.c: In function 'it6505_aux_operation':
>> drivers/gpu/drm/bridge/ite-it6505.c:1004:47: error: implicit declaration of function 'FIELD_GET' [-Wimplicit-function-declaration]
    1004 |         it6505_write(it6505, REG_AUX_CMD_REQ, FIELD_GET(M_AUX_REQ_CMD, cmd));
         |                                               ^~~~~~~~~

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for GET_FREE_REGION
   Depends on [n]: SPARSEMEM [=n]
   Selected by [m]:
   - RESOURCE_KUNIT_TEST [=m] && RUNTIME_TESTING_MENU [=y] && KUNIT [=m]


vim +/FIELD_GET +1004 drivers/gpu/drm/bridge/ite-it6505.c

   956	
   957	static ssize_t it6505_aux_operation(struct it6505 *it6505,
   958					    enum aux_cmd_type cmd,
   959					    unsigned int address, u8 *buffer,
   960					    size_t size, enum aux_cmd_reply *reply)
   961	{
   962		int i, ret;
   963		bool aux_write_check = false;
   964	
   965		if (!it6505_get_sink_hpd_status(it6505))
   966			return -EIO;
   967	
   968		/* set AUX user mode */
   969		it6505_set_bits(it6505, REG_AUX_CTRL, AUX_USER_MODE, AUX_USER_MODE);
   970	
   971	aux_op_start:
   972		/* HW AUX FIFO supports only EDID and DCPD KSV FIFO area */
   973		if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
   974			/* AUX EDID FIFO has max length of AUX_FIFO_MAX_SIZE bytes. */
   975			size = min_t(size_t, size, AUX_FIFO_MAX_SIZE);
   976			/* Enable AUX FIFO read back and clear FIFO */
   977			it6505_set_bits(it6505, REG_AUX_CTRL,
   978					AUX_EN_FIFO_READ | CLR_EDID_FIFO,
   979					AUX_EN_FIFO_READ | CLR_EDID_FIFO);
   980	
   981			it6505_set_bits(it6505, REG_AUX_CTRL,
   982					AUX_EN_FIFO_READ | CLR_EDID_FIFO,
   983					AUX_EN_FIFO_READ);
   984		} else {
   985			/* The DP AUX transmit buffer has 4 bytes. */
   986			size = min_t(size_t, size, 4);
   987			it6505_set_bits(it6505, REG_AUX_CTRL, AUX_NO_SEGMENT_WR,
   988					AUX_NO_SEGMENT_WR);
   989		}
   990	
   991		/* Start Address[7:0] */
   992		it6505_write(it6505, REG_AUX_ADR_0_7, (address >> 0) & 0xFF);
   993		/* Start Address[15:8] */
   994		it6505_write(it6505, REG_AUX_ADR_8_15, (address >> 8) & 0xFF);
   995		/* WriteNum[3:0]+StartAdr[19:16] */
   996		it6505_write(it6505, REG_AUX_ADR_16_19,
   997			     ((address >> 16) & 0x0F) | ((size - 1) << 4));
   998	
   999		if (cmd == CMD_AUX_NATIVE_WRITE)
  1000			regmap_bulk_write(it6505->regmap, REG_AUX_OUT_DATA0, buffer,
  1001					  size);
  1002	
  1003		/* Aux Fire */
> 1004		it6505_write(it6505, REG_AUX_CMD_REQ, FIELD_GET(M_AUX_REQ_CMD, cmd));
  1005	
  1006		ret = it6505_aux_wait(it6505);
  1007		if (ret < 0)
  1008			goto aux_op_err;
  1009	
  1010		ret = it6505_read(it6505, REG_AUX_ERROR_STS);
  1011		if (ret < 0)
  1012			goto aux_op_err;
  1013	
  1014		switch ((ret >> 6) & 0x3) {
  1015		case 0:
  1016			*reply = REPLY_ACK;
  1017			break;
  1018		case 1:
  1019			*reply = REPLY_DEFER;
  1020			ret = -EAGAIN;
  1021			goto aux_op_err;
  1022		case 2:
  1023			*reply = REPLY_NACK;
  1024			ret = -EIO;
  1025			goto aux_op_err;
  1026		case 3:
  1027			ret = -ETIMEDOUT;
  1028			goto aux_op_err;
  1029		}
  1030	
  1031		/* Read back Native Write data */
  1032		if (cmd == CMD_AUX_NATIVE_WRITE) {
  1033			aux_write_check = true;
  1034			cmd = CMD_AUX_NATIVE_READ;
  1035			goto aux_op_start;
  1036		}
  1037	
  1038		if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
  1039			for (i = 0; i < size; i++) {
  1040				ret = it6505_read(it6505, REG_AUX_DATA_FIFO);
  1041				if (ret < 0)
  1042					goto aux_op_err;
  1043				buffer[i] = ret;
  1044			}
  1045		} else {
  1046			for (i = 0; i < size; i++) {
  1047				ret = it6505_read(it6505, REG_AUX_DATA_0_7 + i);
  1048				if (ret < 0)
  1049					goto aux_op_err;
  1050	
  1051				if (aux_write_check && buffer[size - 1 - i] != ret) {
  1052					ret = -EINVAL;
  1053					goto aux_op_err;
  1054				}
  1055	
  1056				buffer[size - 1 - i] = ret;
  1057			}
  1058		}
  1059	
  1060		ret = i;
  1061	
  1062	aux_op_err:
  1063		if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
  1064			/* clear AUX FIFO */
  1065			it6505_set_bits(it6505, REG_AUX_CTRL,
  1066					AUX_EN_FIFO_READ | CLR_EDID_FIFO,
  1067					AUX_EN_FIFO_READ | CLR_EDID_FIFO);
  1068			it6505_set_bits(it6505, REG_AUX_CTRL,
  1069					AUX_EN_FIFO_READ | CLR_EDID_FIFO, 0x00);
  1070		}
  1071	
  1072		/* Leave AUX user mode */
  1073		it6505_set_bits(it6505, REG_AUX_CTRL, AUX_USER_MODE, 0);
  1074	
  1075		return ret;
  1076	}
  1077
Dmitry Baryshkov Oct. 20, 2024, 1:53 p.m. UTC | #3 
On Wed, Oct 16, 2024 at 03:54:15PM +0800, Hermes Wu via B4 Relay wrote:
> From: Hermes Wu <Hermes.wu@ite.com.tw>
> 
> HDCP KSV list readback can choose to use AUX FIFO or
> general data register.
> For some DisplayPort devices, the KSV list must be read
> in 5 byte boundaries.
> The original AUX read command does not support these devices.
> 
> The AUX command operation control register "REG_AUX_CMD_REQ" uses b[3:0]
> as AUX operacion control, and b[7:4] are status bits and read only.
> To change KSV read operation uses "CMD_AUX_NATIVE_READ" from using
> the data registers to using AUX FIFO.
> The extended command "CMD_AUX_GET_KSV_LIST" is added as
> "CMD_AUX_NATIVE_READ" with the 0x10 flag which selects AUX FIFO mode.
> 
> Signed-off-by: Hermes Wu <Hermes.wu@ite.com.tw>
> ---
>  drivers/gpu/drm/bridge/ite-it6505.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 

> @@ -996,7 +1001,7 @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
>  				  size);
>  
>  	/* Aux Fire */
> -	it6505_write(it6505, REG_AUX_CMD_REQ, cmd);
> +	it6505_write(it6505, REG_AUX_CMD_REQ, FIELD_GET(M_AUX_REQ_CMD, cmd));

This needs #include <linux/bitfield.h>

Other than that

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>


>  
>  	ret = it6505_aux_wait(it6505);
>  	if (ret < 0)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 9747d7ccf435d536da55c6a3ff79e504b7c724f0..4e6ec1695ae45111d06026d7548d108fac9e5219 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -126,6 +126,7 @@ 
 #define REG_AUX_OUT_DATA0 0x27
 
 #define REG_AUX_CMD_REQ 0x2B
+#define M_AUX_REQ_CMD 0x0F
 #define AUX_BUSY BIT(5)
 
 #define REG_AUX_DATA_0_7 0x2C
@@ -324,6 +325,9 @@  enum aux_cmd_type {
 	CMD_AUX_NATIVE_READ = 0x0,
 	CMD_AUX_NATIVE_WRITE = 0x5,
 	CMD_AUX_I2C_EDID_READ = 0xB,
+
+	/* KSV read with AUX FIFO extend from CMD_AUX_NATIVE_READ*/
+	CMD_AUX_GET_KSV_LIST = 0x10,
 };
 
 enum aux_cmd_reply {
@@ -965,7 +969,8 @@  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 area */
+	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 */
@@ -996,7 +1001,7 @@  static ssize_t it6505_aux_operation(struct it6505 *it6505,
 				  size);
 
 	/* Aux Fire */
-	it6505_write(it6505, REG_AUX_CMD_REQ, cmd);
+	it6505_write(it6505, REG_AUX_CMD_REQ, FIELD_GET(M_AUX_REQ_CMD, cmd));
 
 	ret = it6505_aux_wait(it6505);
 	if (ret < 0)
@@ -1030,7 +1035,7 @@  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 +1060,7 @@  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,
@@ -1076,7 +1081,8 @@  static ssize_t it6505_aux_do_transfer(struct it6505 *it6505,
 				      size_t size, enum aux_cmd_reply *reply)
 {
 	int i, ret_size, ret = 0, request_size;
-	int fifo_max_size = (cmd == CMD_AUX_I2C_EDID_READ) ? AUX_FIFO_MAX_SIZE : 4;
+	int fifo_max_size = (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) ?
+						 AUX_FIFO_MAX_SIZE : 4;
 
 	mutex_lock(&it6505->aux_lock);
 	i = 0;