On Tue, Nov 12, 2019 at 10:06:00PM +0000, Asmaa Mnebhi wrote: > Also, let me clarify one thing. It doesn't matter how big the response is. In > my testing, I also had some responses that are over 128 bytes, and this > driver still works. It is the user space program which determines the last > bytes received. The 128 bytes is the max number of bytes handled by your > i2c/smbus driver at each i2c transaction. My i2c driver can only transmit 128 > bytes at a time. So just like Corey pointed out, it would be better to pass > this through ACPI/device tree.
Yeah, I would really prefer device tree. That's what it's designed for, really. ioctls are not really what you want for this. sysfs is a better choice as a backup for device tree (so you can change it if it's wrong). -corey > > -----Original Message----- > From: Corey Minyard <tcminy...@gmail.com> On Behalf Of Corey Minyard > Sent: Tuesday, November 12, 2019 3:30 PM > To: Vijay Khemka <vijaykhe...@fb.com> > Cc: Arnd Bergmann <a...@arndb.de>; Greg Kroah-Hartman > <gre...@linuxfoundation.org>; openipmi-developer@lists.sourceforge.net; > linux-ker...@vger.kernel.org; cminy...@mvista.com; Asmaa Mnebhi > <as...@mellanox.com>; j...@jms.id.au; linux-asp...@lists.ozlabs.org; Sai > Dasari <sdas...@fb.com> > Subject: Re: [PATCH 2/2] drivers: ipmi: Modify max length of IPMB packet > > On Tue, Nov 12, 2019 at 07:56:34PM +0000, Vijay Khemka wrote: > > > > > > On 11/12/19, 4:48 AM, "Corey Minyard" <tcminy...@gmail.com on behalf of > > miny...@acm.org> wrote: > > > > On Mon, Nov 11, 2019 at 06:36:10PM -0800, Vijay Khemka wrote: > > > As per IPMB specification, maximum packet size supported is 255, > > > modified Max length to 240 from 128 to accommodate more data. > > > > I couldn't find this in the IPMB specification. > > > > IIRC, the maximum on I2C is 32 byts, and table 6-9 in the IPMI spec, > > under "IPMB Output" states: The IPMB standard message length is > > specified as 32 bytes, maximum, including slave address. > > > > We are using IPMI OEM messages and our response size is around 150 > > bytes For some of responses. That's why I had set it to 240 bytes. > > Hmm. Well, that is a pretty significant violation of the spec, but there's > nothing hard in the protocol that prohibits it, I guess. > > If Asmaa is ok with this, I'm ok with it, too. > > -corey > > > > > I'm not sure where 128 came from, but maybe it should be reduced to 31. > > > > -corey > > > > > > > > Signed-off-by: Vijay Khemka <vijaykhe...@fb.com> > > > --- > > > drivers/char/ipmi/ipmb_dev_int.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/char/ipmi/ipmb_dev_int.c > > b/drivers/char/ipmi/ipmb_dev_int.c > > > index 2419b9a928b2..7f9198bbce96 100644 > > > --- a/drivers/char/ipmi/ipmb_dev_int.c > > > +++ b/drivers/char/ipmi/ipmb_dev_int.c > > > @@ -19,7 +19,7 @@ > > > #include <linux/spinlock.h> > > > #include <linux/wait.h> > > > > > > -#define MAX_MSG_LEN 128 > > > +#define MAX_MSG_LEN 240 > > > #define IPMB_REQUEST_LEN_MIN 7 > > > #define NETFN_RSP_BIT_MASK 0x4 > > > #define REQUEST_QUEUE_MAX_LEN 256 > > > -- > > > 2.17.1 > > > > > > > > > _______________________________________________ > Openipmi-developer mailing list > Openipmi-developer@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/openipmi-developer _______________________________________________ Openipmi-developer mailing list Openipmi-developer@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/openipmi-developer
