On Tue, Aug 22, 2017 at 12:21 AM, Kani, Toshimitsu <toshi.kani@xxxxxxx> wrote: > On Mon, 2017-08-21 at 23:49 +0200, Rafael J. Wysocki wrote: >> On Mon, Aug 21, 2017 at 11:06 PM, Kani, Toshimitsu <toshi.kani@xxxxxx >> m> wrote: >> > On Mon, 2017-08-21 at 22:31 +0200, Rafael J. Wysocki wrote: >> > > On Mon, Aug 21, 2017 at 7:36 PM, Borislav Petkov <bp@xxxxxxxxx> >> > > wrote: >> > > > On Mon, Aug 21, 2017 at 05:23:37PM +0000, Kani, Toshimitsu >> > > > wrote: >> > > > > > > 'data' here is private to the caller. So, I do not think >> > > > > > > we need to define the bits. Shall I change the name to >> > > > > > > 'driver_data' to make it more explicit? >> > > > > > >> > > > > > You changed it to 'data'. It was a u32-used-as-boolean >> > > > > > is_critical_error before. >> > > > > > >> > > > > > So you can just as well make it into flags and people can >> > > > > > extend those flags if needed. A flag bit should be enough >> > > > > > in most cases anyway. If they really need driver_data, then >> > > > > > they can add a void *member. >> > > > > >> > > > > Hmm.. In patch 2, intel_pstate_platform_pwr_mgmt_exists() >> > > > > uses this field for PSS and PCC, which are enum values. I >> > > > > think we should allow drivers to set any values here. I >> > > > > agree that it may need to be void * if we also allow drivers >> > > > > to set a pointer here. >> > > > >> > > > Let's see what Rafael prefers. >> > > >> > > I would retain the is_critical_error field and use that for >> > > printing the recoverable / non-recoverable message. This is kind >> > > of orthogonal to whether or not any extra data is needed and that >> > > can be an additional field. In that case unsigned long should be >> > > sufficient to accommodate a pointer if need be. >> > >> > Yes, we will retain the field. The question is whether this field >> > should be retained as a driver's private data or ACPI-managed >> > flags. >> >> Thanks for the clarification. >> >> > My patch implements the former, which lets the callers to define >> > the data values. For instance, acpi_blacklisted() uses this field >> > as is_critical_error value, and >> > intel_pstate_platform_pwr_mgmt_exists() uses it as oem_pwr_table >> > value. >> > >> > Boris suggested the latter, which lets ACPI to define the flags, >> > which are then used by the callers. For instance, he suggested >> > ACPI to define bit0 as is_critical_error. >> > >> > #define ACPI_PLAT_IS_CRITICAL_ERROR BIT(0) >> >> So my point is that we can have both the ACPI-managed flags and the >> the caller-defined data at the same time as separate items. >> >> That would allow of maximum flexibility IMO. > > I agree in general. Driver private data allows flexibility to drivers > when the values are driver-private. ACPI-managed flags allows ACPI to > control the interfaces based on the flags. > > Since we do not have use-case of the latter case yet, i.e. > acpi_match_platform_list() does not need to check the flags, I'd > suggest that we keep 'data' as driver-private. We can add 'flags' as a > separate member to the structure when we find the latter use-case. OK Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
