RE: [PATCH V4] Input: synaptics-rmi4 - filter incomplete relative packet.

[Marge Yang <Marge.Yang@tw.synaptics.com>]

Hi Dmitry,
	Update Synaptics firmware's comment.
To address the transaction error case in the middle would potential lead to the unexpected data transaction and latency between styk device and host driver.  F$03 didn't really parse any data packet but simply works as bridge functionality to bypass the command and response packets between styk device and driver.

Thanks
Marge Yang

-----Original Message-----
From: Hans de Goede <hdegoede@redhat.com> 
Sent: Wednesday, August 17, 2022 10:12 PM
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 <Marge.Yang@tw.synaptics.com>; Derek Cheng <derek.cheng@tw.synaptics.com>; Vincent Huang <Vincent.huang@tw.synaptics.com>
Subject: Re: [PATCH V4] Input: synaptics-rmi4 - filter incomplete relative packet.

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Hi,

On 8/16/22 11:20, 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>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

note I see that Dmitry still has questions about this, so my Reviewed-by is in no way a guarantee that this will get merged.

Please make sure to answer Dmitry's questions about this.


Regards,

Hans

> ---
>  drivers/input/rmi4/rmi_f03.c | 74 
> +++++++++++++++++++++++++++++++++++-
>  1 file changed, 73 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/input/rmi4/rmi_f03.c 
> b/drivers/input/rmi4/rmi_f03.c index c194b1664b10..563b40c2dc06 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 +326,51 @@ 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;
> +                     }
> +                     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;