Re: hdparm-9.17 released, with experimental trim/wiper scripts for SSDs

[Robert Hancock <hancockrwd@gmail.com>]

On 07/30/2009 06:54 AM, Mark Lord wrote:
>> Yeah, according to the datasheet "The SiI3124 will decode the 8-bit ATA
>> command at PRB offset 0x0a and automatically execute the default
>> protocol for the command. In certain cases it might be desirable to
>> specify a non-default protocol to be used, such as with vendor
>> specific device commands." The DSM command seems to be DMA data-out
>> and the chip likely doesn't know that command. I have to wonder why
>> they decided to use that design instead of just making the driver
>> indicate the protocol explicitly. In any case, it looks like the
>> driver needs code to override the protocol setting for this command.
>> (Maybe we should just set the protocol override for what we know the
>> command is supposed to be in all cases?)
> ..
> 
> If you can puzzle out how to do that, and post a quick(?) patch,
> it would certainly make testing SSDs easier for me here.
> 
> I would like to use the Sil3124 ExpressCard controller with my notebook
> for this stuff, rather than having to power up one of the noisy
> full-size systems under the table.  ;)

You can try this patch (totally untested) which basically just bludgeons it
into doing what we want for all non-packet commands:

diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c
index 77aa8d7..e6946fc 100644
--- a/drivers/ata/sata_sil24.c
+++ b/drivers/ata/sata_sil24.c
@@ -846,6 +846,17 @@ static void sil24_qc_prep(struct ata_queued_cmd *qc)
 	if (!ata_is_atapi(qc->tf.protocol)) {
 		prb = &cb->ata.prb;
 		sge = cb->ata.sge;
+		if (ata_is_data(qc->tf.protocol)) {
+			u16 prot = 0;
+			ctrl = PRB_CTRL_PROTOCOL;
+			if (ata_is_ncq(qc->tf.protocol))
+				prot |= PRB_PROT_NCQ;
+			if (qc->tf.flags & ATA_TFLAG_WRITE)
+				prot |= PRB_PROT_WRITE;
+			else
+				prot |= PRB_PROT_READ;
+			prb->prot = cpu_to_le16(prot);
+		}
 	} else {
 		prb = &cb->atapi.prb;
 		sge = cb->atapi.sge;