Re: Proposed changes for libata speed handling
BTW, for a solution to be complete, we need to halt all work on all other ports, when issuing SET FEATURES - XFER MODE. On SiI and Promise controllers, possibly others, the command is snooped and side effects such as register setting occur. Long standing to-do. Currently we hack around this by serializing the bus probe, and preventing people from issuing SET FEATURES - XFER MODE from userspace. Jeff - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: Proposed changes for libata speed handling
BTW, for a solution to be complete, we need to halt all work on all other ports, when issuing SET FEATURES - XFER MODE. On SiI and Promise controllers, possibly others, the command is snooped and side effects such as register setting occur. Long standing to-do. Currently we hack around this by serializing the bus probe, and preventing people from issuing SET FEATURES - XFER MODE from userspace. Jeff - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: Proposed changes for libata speed handling
Alan wrote:
> O> Wouldn't it be better to have ->determine_xfer_mask() and
>> ->set_specific_mode() than having two somewhat overlapping callbacks?
>> Or is there some problem that can't be handled that way?
>
> I'm not sure I follow what you are suggesting - can you explain further.
>
> Right now ->set_mode does all the policy management with regards to
> picking the right modes which is sometimes done by the usual ATA rules
> and sometimes by card specific code.
>
> ->set_specific_mode does no policy work but merely sets up a mode.
>
> The default behaviour of ->set_mode() is the ATA mode selection by best
> mode available, and this function is normally not provided by a driver.
>
> The default behaviour of ->set_specific_mode() is to verify the mode is
> valid then issue ->set_pio|dma_mode() (for both devices in case a timing
> change on both is triggered). This function is overridable because of
> things like IT821x where the IDE mode is imaginary.
What I was thinking about was something like the following.
* ops
unsigned int (*determine_xfer_mask)(struct ata_device *dev);
int (*set_specific_mode)(struct ata_device *dev,
unsigned int xfer_mode);
* during init and EH
if (init) {
ap->xfer_mask &= ops->determine_xfer_mask(dev);
DETERMINE best_mode;
}
if (ap->ehi.target_mode && valid)
mode = ap->ehi.target_mode;
else
mode = best_mode;
rc = ops->set_specific_mode(dev, mode);
* when the user issues SET_XFERMODE, in the issue path
if (command is SET_XFERMODE) {
if (mode is invalid)
fail;
ap->ehi.target_mode = user_specified_mode;
ata_port_schedule_eh(ap);
done;
}
To sum up,
1. separate supported mode detection and mode programming such that we
can use the same programming path for both init and handling user-issued
SET_XFERMODE.
2. group all mode programming callbacks (->set_piomode, ->set_dmamode
and ->post_set_mode into ->set_specific_mode) into ->set_specific_mode
to allow more flexibility and replace ->set_mode.
3. make sure all xfer mode programming is done in EH. this will ease
support for weird controllers (e.g. cross-port synchronization).
Thanks.
--
tejun
-
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Re: Proposed changes for libata speed handling
Alan wrote:
O Wouldn't it be better to have -determine_xfer_mask() and
-set_specific_mode() than having two somewhat overlapping callbacks?
Or is there some problem that can't be handled that way?
I'm not sure I follow what you are suggesting - can you explain further.
Right now -set_mode does all the policy management with regards to
picking the right modes which is sometimes done by the usual ATA rules
and sometimes by card specific code.
-set_specific_mode does no policy work but merely sets up a mode.
The default behaviour of -set_mode() is the ATA mode selection by best
mode available, and this function is normally not provided by a driver.
The default behaviour of -set_specific_mode() is to verify the mode is
valid then issue -set_pio|dma_mode() (for both devices in case a timing
change on both is triggered). This function is overridable because of
things like IT821x where the IDE mode is imaginary.
What I was thinking about was something like the following.
* ops
unsigned int (*determine_xfer_mask)(struct ata_device *dev);
int (*set_specific_mode)(struct ata_device *dev,
unsigned int xfer_mode);
* during init and EH
if (init) {
ap-xfer_mask = ops-determine_xfer_mask(dev);
DETERMINE best_mode;
}
if (ap-ehi.target_mode valid)
mode = ap-ehi.target_mode;
else
mode = best_mode;
rc = ops-set_specific_mode(dev, mode);
* when the user issues SET_XFERMODE, in the issue path
if (command is SET_XFERMODE) {
if (mode is invalid)
fail;
ap-ehi.target_mode = user_specified_mode;
ata_port_schedule_eh(ap);
done;
}
To sum up,
1. separate supported mode detection and mode programming such that we
can use the same programming path for both init and handling user-issued
SET_XFERMODE.
2. group all mode programming callbacks (-set_piomode, -set_dmamode
and -post_set_mode into -set_specific_mode) into -set_specific_mode
to allow more flexibility and replace -set_mode.
3. make sure all xfer mode programming is done in EH. this will ease
support for weird controllers (e.g. cross-port synchronization).
Thanks.
--
tejun
-
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the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: Proposed changes for libata speed handling
O> Wouldn't it be better to have ->determine_xfer_mask() and > ->set_specific_mode() than having two somewhat overlapping callbacks? > Or is there some problem that can't be handled that way? I'm not sure I follow what you are suggesting - can you explain further. Right now ->set_mode does all the policy management with regards to picking the right modes which is sometimes done by the usual ATA rules and sometimes by card specific code. ->set_specific_mode does no policy work but merely sets up a mode. The default behaviour of ->set_mode() is the ATA mode selection by best mode available, and this function is normally not provided by a driver. The default behaviour of ->set_specific_mode() is to verify the mode is valid then issue ->set_pio|dma_mode() (for both devices in case a timing change on both is triggered). This function is overridable because of things like IT821x where the IDE mode is imaginary. Alan - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: Proposed changes for libata speed handling
O Wouldn't it be better to have -determine_xfer_mask() and -set_specific_mode() than having two somewhat overlapping callbacks? Or is there some problem that can't be handled that way? I'm not sure I follow what you are suggesting - can you explain further. Right now -set_mode does all the policy management with regards to picking the right modes which is sometimes done by the usual ATA rules and sometimes by card specific code. -set_specific_mode does no policy work but merely sets up a mode. The default behaviour of -set_mode() is the ATA mode selection by best mode available, and this function is normally not provided by a driver. The default behaviour of -set_specific_mode() is to verify the mode is valid then issue -set_pio|dma_mode() (for both devices in case a timing change on both is triggered). This function is overridable because of things like IT821x where the IDE mode is imaginary. Alan - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: Proposed changes for libata speed handling
Alan wrote:
> I'm currently hacking on the speed handling code a bit
>
> I'd like to do the following unless anyone has any objections
>
> - Remove post_set_mode and make drivers wrap the guts of the existing
> set_mode() function. This allows a driver to wrap and see success/failure
> while removing a callback, and also to add pre-mode code. (ie you'd do
>
> foo_set_mode() {
> ata_default_set_mode()
> my_fiddling();
> }
>
> - Fix the ->set_mode method FIXMEs in the current tree [DONE]
>
> - Add set_specific_mode, with a default behaviour that works for most
> controllers. Those using a private ->set_mode might need a private
> ->set_specific_mode, in some cases like it8212 simply to error the request
>
> - Hook set_specific_mode to the ata command parser so that instead of
> erroring set_features commands we snoop them and force the mode change
> desired on the controller (if valid)
>
> - Send the command to set the speed before setting the controller speed,
> so that we send them at the right rate.
>
> Any comments ?
Wouldn't it be better to have ->determine_xfer_mask() and
->set_specific_mode() than having two somewhat overlapping callbacks?
Or is there some problem that can't be handled that way?
Thanks.
--
tejun
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Proposed changes for libata speed handling
I'm currently hacking on the speed handling code a bit
I'd like to do the following unless anyone has any objections
- Remove post_set_mode and make drivers wrap the guts of the existing
set_mode() function. This allows a driver to wrap and see success/failure
while removing a callback, and also to add pre-mode code. (ie you'd do
foo_set_mode() {
ata_default_set_mode()
my_fiddling();
}
- Fix the ->set_mode method FIXMEs in the current tree [DONE]
- Add set_specific_mode, with a default behaviour that works for most
controllers. Those using a private ->set_mode might need a private
->set_specific_mode, in some cases like it8212 simply to error the request
- Hook set_specific_mode to the ata command parser so that instead of
erroring set_features commands we snoop them and force the mode change
desired on the controller (if valid)
- Send the command to set the speed before setting the controller speed,
so that we send them at the right rate.
Any comments ?
Alan
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Proposed changes for libata speed handling
I'm currently hacking on the speed handling code a bit
I'd like to do the following unless anyone has any objections
- Remove post_set_mode and make drivers wrap the guts of the existing
set_mode() function. This allows a driver to wrap and see success/failure
while removing a callback, and also to add pre-mode code. (ie you'd do
foo_set_mode() {
ata_default_set_mode()
my_fiddling();
}
- Fix the -set_mode method FIXMEs in the current tree [DONE]
- Add set_specific_mode, with a default behaviour that works for most
controllers. Those using a private -set_mode might need a private
-set_specific_mode, in some cases like it8212 simply to error the request
- Hook set_specific_mode to the ata command parser so that instead of
erroring set_features commands we snoop them and force the mode change
desired on the controller (if valid)
- Send the command to set the speed before setting the controller speed,
so that we send them at the right rate.
Any comments ?
Alan
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: Proposed changes for libata speed handling
Alan wrote:
I'm currently hacking on the speed handling code a bit
I'd like to do the following unless anyone has any objections
- Remove post_set_mode and make drivers wrap the guts of the existing
set_mode() function. This allows a driver to wrap and see success/failure
while removing a callback, and also to add pre-mode code. (ie you'd do
foo_set_mode() {
ata_default_set_mode()
my_fiddling();
}
- Fix the -set_mode method FIXMEs in the current tree [DONE]
- Add set_specific_mode, with a default behaviour that works for most
controllers. Those using a private -set_mode might need a private
-set_specific_mode, in some cases like it8212 simply to error the request
- Hook set_specific_mode to the ata command parser so that instead of
erroring set_features commands we snoop them and force the mode change
desired on the controller (if valid)
- Send the command to set the speed before setting the controller speed,
so that we send them at the right rate.
Any comments ?
Wouldn't it be better to have -determine_xfer_mask() and
-set_specific_mode() than having two somewhat overlapping callbacks?
Or is there some problem that can't be handled that way?
Thanks.
--
tejun
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
