| Message ID | 1436351118-3360-1-git-send-email-ellen@cumulusnetworks.com |
|---|---|
| State | Superseded |
| Headers | show |
On Wednesday 08 July 2015 03:55 PM, Ellen Wang wrote: > cp2112_i2c_xfer() only reads up to 61 bytes, returning EIO > on longers reads. The fix is to wrap a loop around > cp2112_read() to pick up all the returned data. > > Signed-off-by: Ellen Wang <ellen@cumulusnetworks.com> > --- > This is the updated patch with a check for 0 return from > cp2112_read(). I tested it with a suitable delay in the loop > to trigger the cp2112_raw_event() overrun bug, which must > be fixed before this patch is applied. > --- > drivers/hid/hid-cp2112.c | 33 ++++++++++++++++++++++++++------- > 1 file changed, 26 insertions(+), 7 deletions(-) > > diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c > index 3318de6..e2ffac0 100644 > --- a/drivers/hid/hid-cp2112.c > +++ b/drivers/hid/hid-cp2112.c > @@ -509,13 +509,32 @@ static int cp2112_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > if (!(msgs->flags & I2C_M_RD)) > goto finish; > > - ret = cp2112_read(dev, msgs->buf, msgs->len); > - if (ret < 0) > - goto power_normal; > - if (ret != msgs->len) { > - hid_warn(hdev, "short read: %d < %d\n", ret, msgs->len); > - ret = -EIO; > - goto power_normal; > + for (count = 0; count < msgs->len;) { > + ret = cp2112_read(dev, msgs->buf + count, msgs->len - count); > + hid_warn(hdev, "read returned %d for %zd\n", > + ret, msgs->len - count); Do you always want to throw warning here, unconditionally ? > + if (ret < 0) > + goto power_normal; > + if (ret == 0) { > + hid_err(hdev, "read returned 0\n"); > + ret = -EIO; > + goto power_normal; > + } bit simplified, I guess :) if (ret < 0 || ret == 0) { hid_err(hdev, "read returned %d", ret); ret = ret == 0 ? -EIO : ret; goto power_normal; } > + count += ret; > + if (count > msgs->len) { > + /* > + * The hardware returned too much data. > + * This is mostly harmless because cp2112_read() > + * has a limit check so didn't overrun our > + * buffer. Nevertheless, we return an error > + * because something is seriously wrong and > + * it shouldn't go unnoticed. > + */ > + hid_err(hdev, "long read: %d > %zd\n", > + ret, msgs->len - count + ret); You may want to take another look here. 'ret' will be either, - ret = msgs->len Not applicable - ret > msgs->len (count > msgs->len) will happen in one single iteration, and will - ret < msgs->len (count > msgs->len) will happen in multiple iterations where count keeps incrementing based on ret In the 2 scenarios above, I believe you would want to show, actual read bytes > requested read bytes Am I missing something here? Thanks, Vaibhav -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 07/08/2015 05:07 AM, Vaibhav Hiremath wrote: > > > On Wednesday 08 July 2015 03:55 PM, Ellen Wang wrote: >> cp2112_i2c_xfer() only reads up to 61 bytes, returning EIO >> on longers reads. The fix is to wrap a loop around >> cp2112_read() to pick up all the returned data. >> >> Signed-off-by: Ellen Wang <ellen@cumulusnetworks.com> >> --- >> This is the updated patch with a check for 0 return from >> cp2112_read(). I tested it with a suitable delay in the loop >> to trigger the cp2112_raw_event() overrun bug, which must >> be fixed before this patch is applied. >> --- >> drivers/hid/hid-cp2112.c | 33 ++++++++++++++++++++++++++------- >> 1 file changed, 26 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c >> index 3318de6..e2ffac0 100644 >> --- a/drivers/hid/hid-cp2112.c >> +++ b/drivers/hid/hid-cp2112.c >> @@ -509,13 +509,32 @@ static int cp2112_i2c_xfer(struct i2c_adapter >> *adap, struct i2c_msg *msgs, >> if (!(msgs->flags & I2C_M_RD)) >> goto finish; >> >> - ret = cp2112_read(dev, msgs->buf, msgs->len); >> - if (ret < 0) >> - goto power_normal; >> - if (ret != msgs->len) { >> - hid_warn(hdev, "short read: %d < %d\n", ret, msgs->len); >> - ret = -EIO; >> - goto power_normal; >> + for (count = 0; count < msgs->len;) { >> + ret = cp2112_read(dev, msgs->buf + count, msgs->len - count); >> + hid_warn(hdev, "read returned %d for %zd\n", >> + ret, msgs->len - count); > > Do you always want to throw warning here, unconditionally ? Yeah. Sorry. I had debugging code in my workspace then ran git diff with the wrong options. I'll resend. >> + if (ret < 0) >> + goto power_normal; >> + if (ret == 0) { >> + hid_err(hdev, "read returned 0\n"); >> + ret = -EIO; >> + goto power_normal; >> + } > > bit simplified, I guess :) > > if (ret < 0 || ret == 0) { > hid_err(hdev, "read returned %d", ret); > ret = ret == 0 ? -EIO : ret; > goto power_normal; > } > > >> + count += ret; >> + if (count > msgs->len) { >> + /* >> + * The hardware returned too much data. >> + * This is mostly harmless because cp2112_read() >> + * has a limit check so didn't overrun our >> + * buffer. Nevertheless, we return an error >> + * because something is seriously wrong and >> + * it shouldn't go unnoticed. >> + */ >> + hid_err(hdev, "long read: %d > %zd\n", >> + ret, msgs->len - count + ret); > > You may want to take another look here. > 'ret' will be either, > > - ret = msgs->len > Not applicable > - ret > msgs->len > (count > msgs->len) will happen in one single > iteration, and will > - ret < msgs->len > (count > msgs->len) will happen in multiple iterations > where count keeps incrementing based on ret > > In the 2 scenarios above, I believe you would want to show, > > actual read bytes > requested read bytes > > > Am I missing something here? (count > msgs->len) should never happen, so there's really no predicting it. Or do you mean something else? > Thanks, > Vaibhav Thank you. -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wednesday 08 July 2015 11:38 PM, Ellen Wang wrote: > > > On 07/08/2015 05:07 AM, Vaibhav Hiremath wrote: >> >> >> On Wednesday 08 July 2015 03:55 PM, Ellen Wang wrote: >>> cp2112_i2c_xfer() only reads up to 61 bytes, returning EIO >>> on longers reads. The fix is to wrap a loop around >>> cp2112_read() to pick up all the returned data. >>> >>> Signed-off-by: Ellen Wang <ellen@cumulusnetworks.com> >>> --- >>> This is the updated patch with a check for 0 return from >>> cp2112_read(). I tested it with a suitable delay in the loop >>> to trigger the cp2112_raw_event() overrun bug, which must >>> be fixed before this patch is applied. >>> --- >>> drivers/hid/hid-cp2112.c | 33 ++++++++++++++++++++++++++------- >>> 1 file changed, 26 insertions(+), 7 deletions(-) >>> >>> diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c >>> index 3318de6..e2ffac0 100644 >>> --- a/drivers/hid/hid-cp2112.c >>> +++ b/drivers/hid/hid-cp2112.c >>> @@ -509,13 +509,32 @@ static int cp2112_i2c_xfer(struct i2c_adapter >>> *adap, struct i2c_msg *msgs, >>> if (!(msgs->flags & I2C_M_RD)) >>> goto finish; >>> >>> - ret = cp2112_read(dev, msgs->buf, msgs->len); >>> - if (ret < 0) >>> - goto power_normal; >>> - if (ret != msgs->len) { >>> - hid_warn(hdev, "short read: %d < %d\n", ret, msgs->len); >>> - ret = -EIO; >>> - goto power_normal; >>> + for (count = 0; count < msgs->len;) { >>> + ret = cp2112_read(dev, msgs->buf + count, msgs->len - count); >>> + hid_warn(hdev, "read returned %d for %zd\n", >>> + ret, msgs->len - count); >> >> Do you always want to throw warning here, unconditionally ? > > Yeah. Sorry. I had debugging code in my workspace then ran git diff > with the wrong options. I'll resend. > >>> + if (ret < 0) >>> + goto power_normal; >>> + if (ret == 0) { >>> + hid_err(hdev, "read returned 0\n"); >>> + ret = -EIO; >>> + goto power_normal; >>> + } >> >> bit simplified, I guess :) >> >> if (ret < 0 || ret == 0) { >> hid_err(hdev, "read returned %d", ret); >> ret = ret == 0 ? -EIO : ret; >> goto power_normal; >> } >> >> >>> + count += ret; >>> + if (count > msgs->len) { >>> + /* >>> + * The hardware returned too much data. >>> + * This is mostly harmless because cp2112_read() >>> + * has a limit check so didn't overrun our >>> + * buffer. Nevertheless, we return an error >>> + * because something is seriously wrong and >>> + * it shouldn't go unnoticed. >>> + */ >>> + hid_err(hdev, "long read: %d > %zd\n", >>> + ret, msgs->len - count + ret); >> >> You may want to take another look here. >> 'ret' will be either, >> >> - ret = msgs->len >> Not applicable >> - ret > msgs->len >> (count > msgs->len) will happen in one single >> iteration, and will >> - ret < msgs->len >> (count > msgs->len) will happen in multiple iterations >> where count keeps incrementing based on ret >> >> In the 2 scenarios above, I believe you would want to show, >> >> actual read bytes > requested read bytes >> >> >> Am I missing something here? > > (count > msgs->len) should never happen, so there's really no predicting > it. Or do you mean something else? > I meant the message which you are printing above seems wrong to me. Thanks, Vaibhav > >> Thanks, >> Vaibhav > > Thank you. -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 07/09/2015 01:07 AM, Vaibhav Hiremath wrote: > ... >>>> + count += ret; >>>> + if (count > msgs->len) { >>>> + /* >>>> + * The hardware returned too much data. >>>> + * This is mostly harmless because cp2112_read() >>>> + * has a limit check so didn't overrun our >>>> + * buffer. Nevertheless, we return an error >>>> + * because something is seriously wrong and >>>> + * it shouldn't go unnoticed. >>>> + */ >>>> + hid_err(hdev, "long read: %d > %zd\n", >>>> + ret, msgs->len - count + ret); >>> >>> You may want to take another look here. >>> 'ret' will be either, >>> >>> - ret = msgs->len >>> Not applicable >>> - ret > msgs->len >>> (count > msgs->len) will happen in one single >>> iteration, and will >>> - ret < msgs->len >>> (count > msgs->len) will happen in multiple iterations >>> where count keeps incrementing based on ret >>> >>> In the 2 scenarios above, I believe you would want to show, >>> >>> actual read bytes > requested read bytes >>> >>> >>> Am I missing something here? >> >> (count > msgs->len) should never happen, so there's really no predicting >> it. Or do you mean something else? >> > > I meant the message which you are printing above seems wrong to me. It does print the size of the read request. I guess I could have written it as msgs->len - (count - ret). Or I'm still missing what you mean. -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c index 3318de6..e2ffac0 100644 --- a/drivers/hid/hid-cp2112.c +++ b/drivers/hid/hid-cp2112.c @@ -509,13 +509,32 @@ static int cp2112_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, if (!(msgs->flags & I2C_M_RD)) goto finish; - ret = cp2112_read(dev, msgs->buf, msgs->len); - if (ret < 0) - goto power_normal; - if (ret != msgs->len) { - hid_warn(hdev, "short read: %d < %d\n", ret, msgs->len); - ret = -EIO; - goto power_normal; + for (count = 0; count < msgs->len;) { + ret = cp2112_read(dev, msgs->buf + count, msgs->len - count); + hid_warn(hdev, "read returned %d for %zd\n", + ret, msgs->len - count); + if (ret < 0) + goto power_normal; + if (ret == 0) { + hid_err(hdev, "read returned 0\n"); + ret = -EIO; + goto power_normal; + } + count += ret; + if (count > msgs->len) { + /* + * The hardware returned too much data. + * This is mostly harmless because cp2112_read() + * has a limit check so didn't overrun our + * buffer. Nevertheless, we return an error + * because something is seriously wrong and + * it shouldn't go unnoticed. + */ + hid_err(hdev, "long read: %d > %zd\n", + ret, msgs->len - count + ret); + ret = -EIO; + goto power_normal; + } } finish:
cp2112_i2c_xfer() only reads up to 61 bytes, returning EIO on longers reads. The fix is to wrap a loop around cp2112_read() to pick up all the returned data. Signed-off-by: Ellen Wang <ellen@cumulusnetworks.com> --- This is the updated patch with a check for 0 return from cp2112_read(). I tested it with a suitable delay in the loop to trigger the cp2112_raw_event() overrun bug, which must be fixed before this patch is applied. --- drivers/hid/hid-cp2112.c | 33 ++++++++++++++++++++++++++------- 1 file changed, 26 insertions(+), 7 deletions(-)