On Thu, Aug 04, 2016 at 12:35:59PM +0200, Enric Balletbo Serra wrote: > 2016-07-12 12:13 GMT+02:00 Daniel Vetter <daniel@xxxxxxxx>: > > On Wed, Jun 29, 2016 at 6:31 AM, Daniel Kurtz <djkurtz@xxxxxxxxxxxx> wrote: > >> On Fri, Jun 17, 2016 at 3:14 AM, Emil Velikov <emil.l.velikov@xxxxxxxxx> wrote: > >>>> +static ssize_t ps8640_update_fw_store(struct device *dev, > >>>> + struct device_attribute *attr, > >>>> + const char *buf, size_t count) > >>>> +{ > >>>> + struct i2c_client *client = to_i2c_client(dev); > >>>> + struct ps8640 *ps_bridge = i2c_get_clientdata(client); > >>>> + const struct firmware *fw; > >>>> + int error; > >>>> + > >>>> + error = request_firmware(&fw, PS_FW_NAME, dev); > >>> Can the device operate without a firmware ? If not, why is the > >>> firmware loaded so later/after user interaction (via sysfs) ? I don't > >>> recall any other driver in DRM to use such an approach. > >> > >> The PS8640 has internal flash, so it should always already have a > >> working firmware. > >> This sysfs interface is useful for user space initiated field firmware updates. > > > > Might be better to just do a request_firmware on driver load, and > > simply proceed if it's not there. Adding a sysfs interface (which is > > abi) seems way too much overkill for this imo. If you want to upgrade > > the firmware you can then just drop it into the right directory, with > > no further interaction needed. > > IMHO I'm not sure if for this use case request_firmware on driver load > is a good idea. Flash the non-volatile internal chip can be a slow > operation and if you forget to remove the firmware after drop it into > the right directory apart from slow down the driver probe you can > damage the chip depending on the write endurance of the chip. Ah ok. Explaining this in the commit message would be really good. > This sysfs interface is used on other subsystems when there is a > non-volatile memory, as example you can see at [1], [2]. Unfortunately > not all are using the same sysfs interface and maybe this should be > standardized (maybe it's an opportunity to define it) +1 on standardizing this. -Daniel > > Regards, > Enric > > [1] http://lxr.free-electrons.com/source/drivers/input/touchscreen/wdt87xx_i2c.c#L922 > [2] http://lxr.free-electrons.com/source/drivers/scsi/pm8001/pm8001_ctl.c#L732 > > > > -Daniel > > -- > > Daniel Vetter > > Software Engineer, Intel Corporation > > +41 (0) 79 365 57 48 - http://blog.ffwll.ch > > _______________________________________________ > > dri-devel mailing list > > dri-devel@xxxxxxxxxxxxxxxxxxxxx > > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html