Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.36 as permitted sender) client-ip=23.128.96.36;
Subject: Re: [PATCH 4/4] ata: pata_parport: fit3: implement IDE command set
 registers
To:     Ondrej Zary <linux@zary.sk>, Damien Le Moal <dlemoal@kernel.org>,
        Sudip Mukherjee <sudipm.mukherjee@gmail.com>
CC:     Christoph Hellwig <hch@lst.de>, Tim Waugh <tim@cyberelk.net>,
        <linux-parport@lists.infradead.org>, <linux-ide@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
References: <20231005192440.4047-1-linux@zary.sk>
 <20231005192440.4047-5-linux@zary.sk>
From:   Sergey Shtylyov <s.shtylyov@omp.ru>
Organization: Open Mobile Platform
Message-ID: <c2e074e0-ad91-e8b4-debf-00661ad5c720@omp.ru>
Date:   Thu, 5 Oct 2023 22:53:44 +0300
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.10.1
MIME-Version: 1.0
In-Reply-To: <20231005192440.4047-5-linux@zary.sk>
Content-Type: text/plain; charset="utf-8"
Content-Language: en-US
Content-Transfer-Encoding: 7bit
X-KSE-Attachment-Filter-Triggered-Filters: Clean
X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit
X-Spam-Status: No, score=-5.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS
	autolearn=unavailable autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on pete.vger.email
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (pete.vger.email [0.0.0.0]); Thu, 05 Oct 2023 12:54:02 -0700 (PDT)

On 10/5/23 10:24 PM, Ondrej Zary wrote:

> fit3 protocol driver does not support accessing IDE control registers
> (device control/altstatus). The DOS driver does not use these registers
> either (as observed from DOSEMU trace). But the HW seems to be capable
> of accessing these registers - I simply tried bit 3 and it works!
> 
> The control register is required to properly reset ATAPI devices or
> they will be detected only once (after a power cycle).
> 
> Tested with EXP Computer CD-865 with MC-1285B EPP cable and
> TransDisk 3000.
> 
> Signed-off-by: Ondrej Zary <linux@zary.sk>

Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>

> ---
>  drivers/ata/pata_parport/fit3.c | 14 ++------------
>  1 file changed, 2 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/ata/pata_parport/fit3.c b/drivers/ata/pata_parport/fit3.c
> index bad7aa920cdc..d2b81cf2e16d 100644
> --- a/drivers/ata/pata_parport/fit3.c
> +++ b/drivers/ata/pata_parport/fit3.c
[...]
> @@ -59,11 +53,7 @@ static int fit3_read_regr(struct pi_adapter *pi, int cont, int regr)
>  {
>  	int  a, b;
>  
> -	if (cont) {
> -		if (regr != 6)
> -			return 0xff;
> -		regr = 7;
> -	}
> +	regr += cont << 3;

   So, is regr == 7 instead of 8 intentional?

[...]

MBR, Sergey