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Message-ID: <7d6718e0-5dfa-c688-8ae3-1cf8d0eba79c@redhat.com>
Date:   Mon, 15 Aug 2022 13:11:59 +0200
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Subject: Re: [PATCH V3] Input: synaptics-rmi4 - filter incomplete relative
 packet.
Content-Language: en-US
To:     margeyang <marge.yang@synaptics.corp-partner.google.com>,
        dmitry.torokhov@gmail.com, linux-input@vger.kernel.org,
        linux-kernel@vger.kernel.org, benjamin.tissoires@redhat.com
Cc:     marge.yang@tw.synaptics.com, derek.cheng@tw.synaptics.com,
        vincent.huang@tw.synaptics.com
References: <1660559273-5387-1-git-send-email-marge.yang@synaptics.corp-partner.google.com>
From:   Hans de Goede <hdegoede@redhat.com>
In-Reply-To: <1660559273-5387-1-git-send-email-marge.yang@synaptics.corp-partner.google.com>
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Precedence: bulk

Hi,

On 8/15/22 12:27, margeyang wrote:
> From: Marge Yang <marge.yang@synaptics.corp-partner.google.com>
> 
> RMI4 F03 supports the Stick function,
> it's designed to support relative packet.
> This patch supports the following case.
> When relative packet can't be reported completely,
> it may miss one byte or two byte.
> New Synaptics firmware will report PARITY error.
> When timeout error or parity error happens,
> RMI4 driver will sends 0xFE command and
> ask FW to Re-send stick packet again.
> 
> Signed-off-by: Marge Yang<marge.yang@synaptics.corp-partner.google.com>
> ---
>  drivers/input/rmi4/rmi_f03.c | 77 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 76 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/rmi4/rmi_f03.c b/drivers/input/rmi4/rmi_f03.c
> index c194b1664b10..05076db83808 100644
> --- a/drivers/input/rmi4/rmi_f03.c
> +++ b/drivers/input/rmi4/rmi_f03.c
> @@ -23,8 +23,12 @@
>  #define RMI_F03_BYTES_PER_DEVICE_SHIFT	4
>  #define RMI_F03_QUEUE_LENGTH		0x0F
>  
> +#define RMI_F03_RESET_STYK		0xFE
> +
>  #define PSMOUSE_OOB_EXTRA_BTNS		0x01
>  
> +#define RELATIVE_PACKET_SIZE		3
> +
>  struct f03_data {
>  	struct rmi_function *fn;
>  
> @@ -33,6 +37,11 @@ struct f03_data {
>  
>  	unsigned int overwrite_buttons;
>  
> +	int iwritecommandcounter;
> +	unsigned int ipacketindex;
> +	unsigned int serio_flagsArry[RELATIVE_PACKET_SIZE];
> +	u8 ob_dataArry[RELATIVE_PACKET_SIZE];
> +
>  	u8 device_count;
>  	u8 rx_queue_length;
>  };
> @@ -88,6 +97,7 @@ static int rmi_f03_pt_write(struct serio *id, unsigned char val)
>  		return error;
>  	}
>  
> +	f03->iwritecommandcounter++;
>  	return 0;
>  }
>  
> @@ -107,6 +117,8 @@ static int rmi_f03_initialize(struct f03_data *f03)
>  		return error;
>  	}
>  
> +	f03->iwritecommandcounter = 0;
> +	f03->ipacketindex = 0;
>  	f03->device_count = query1 & RMI_F03_DEVICE_COUNT;
>  	bytes_per_device = (query1 >> RMI_F03_BYTES_PER_DEVICE_SHIFT) &
>  				RMI_F03_BYTES_PER_DEVICE;
> @@ -284,6 +296,22 @@ static irqreturn_t rmi_f03_attention(int irq, void *ctx)
>  		ob_data = obs[i + RMI_F03_OB_DATA_OFFSET];
>  		serio_flags = 0;
>  
> +		if (ob_status & (RMI_F03_OB_FLAG_TIMEOUT | RMI_F03_OB_FLAG_PARITY)) {
> +			//  Send resend command to stick when timeout or parity error.
> +			//  Driver can receive the last stick packet.
> +			unsigned char val = RMI_F03_RESET_STYK;
> +
> +			error = rmi_write(f03->fn->rmi_dev, f03->fn->fd.data_base_addr, val);
> +			if (error) {
> +				dev_err(&f03->fn->dev,
> +					"%s: Failed to rmi_write to F03 TX register (%d).\n",
> +					__func__, error);
> +				return error;
> +			}
> +			f03->ipacketindex = 0;
> +			break;
> +		}
> +
>  		if (!(ob_status & RMI_F03_RX_DATA_OFB))
>  			continue;
>  
> @@ -298,7 +326,54 @@ static irqreturn_t rmi_f03_attention(int irq, void *ctx)
>  			serio_flags & SERIO_TIMEOUT ?  'Y' : 'N',
>  			serio_flags & SERIO_PARITY ? 'Y' : 'N');
>  
> -		serio_interrupt(f03->serio, ob_data, serio_flags);
> +		if (f03->iwritecommandcounter > 0) {
> +			// Read Acknowledge Byte after writing the PS2 command.
> +			// It is not trackpoint data.
> +			serio_interrupt(f03->serio, ob_data, serio_flags);
> +		} else {
> +			//   The relative-mode PS/2 packet format is as follows:
> +			//
> +			//              bit position            position (as array of bytes)
> +			//     7   6   5   4   3   2   1   0
> +			//   =================================+
> +			//    Yov Xov DY8 DX8  1   M   R   L  | DATA[0]
> +			//                DX[7:0]             | DATA[1]
> +			//                DY[7:0]             | DATA[2]
> +			//   =================================+
> +			//		Yov: Y overflow
> +			//    Xov: X overflow
> +			if ((f03->ipacketindex == 0) && (ob_data & ((BIT(7)|BIT(6))))) {
> +				dev_err(&f03->fn->dev,
> +				"%s: X or Y is overflow. (%x)\n",
> +				__func__, ob_data);
> +				break;
> +			} else if ((f03->ipacketindex == 0) && !(ob_data & BIT(3))) {
> +				dev_err(&f03->fn->dev,
> +				"%s: New BIT 3 is not 1 for the first byte\n",
> +				__func__);
> +				break;
> +			}
> +			if (f03->ipacketindex >= RELATIVE_PACKET_SIZE)
> +				f03->ipacketindex = 0;

(f03->ipacketindex >= RELATIVE_PACKET_SIZE) is never true at this point, since it
gets reset to 0 when it reaches RELATIVE_PACKET_SIZE below already.

So these 2 lines can be dropped.

Regards,

Hans


> +
> +			f03->ob_dataArry[f03->ipacketindex] = ob_data;
> +			f03->serio_flagsArry[f03->ipacketindex] = serio_flags;
> +			f03->ipacketindex++;
> +
> +			if (f03->ipacketindex == RELATIVE_PACKET_SIZE)	{
> +				serio_interrupt(f03->serio, f03->ob_dataArry[0],
> +				 f03->serio_flagsArry[0]);
> +				serio_interrupt(f03->serio, f03->ob_dataArry[1],
> +				 f03->serio_flagsArry[1]);
> +				serio_interrupt(f03->serio, f03->ob_dataArry[2],
> +				 f03->serio_flagsArry[2]);
> +				f03->ipacketindex = 0;
> +			}
> +		}
> +	}
> +	if (f03->iwritecommandcounter > 0) {
> +		f03->ipacketindex = 0;
> +		f03->iwritecommandcounter = f03->iwritecommandcounter - 1;
>  	}
>  
>  	return IRQ_HANDLED;