Re: touchscreen: edt-ft5x06: Prevent DMA driver from mapping an area on stack
Hello, On 15-12-12 20:42:37, Dmitry Torokhov wrote: > On Sat, Dec 12, 2015 at 06:13:55PM +0100, Wolfram Sang wrote: > > > > > Frankly speaking I do not know where the fix should actually be. I2C IMX > > > driver somehow taking care of this or the users of I2C, touchscreen > > > drivers > > > in this case. In my opinion, the fix should be with the touchscreen driver > > > however I did like to have feedback or hear opinions on what is the > > > accepted > > > solution to this. > > > > There is no accepted solution to this yet :( DMA is/was still too rare for > > a serious discussion about this. There is also [1] and probably more... > > > > [1] http://patchwork.ozlabs.org/patch/220137/ > > I believe vast majority of i2c client drivers do not expect that the > transfer buffer they supply in i2c messages are supposed to be DMAable > (unlike USB and SPI buses that had that requirement from the beginning). > > I won't be applying this patch unless we decide that I2C changes the > rules. Understood. Thanks for the clarifications Dmitry and Wolfram. - Sanchayan. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: touchscreen: edt-ft5x06: Prevent DMA driver from mapping an area on stack
Hello, On 15-12-12 20:42:37, Dmitry Torokhov wrote: > On Sat, Dec 12, 2015 at 06:13:55PM +0100, Wolfram Sang wrote: > > > > > Frankly speaking I do not know where the fix should actually be. I2C IMX > > > driver somehow taking care of this or the users of I2C, touchscreen > > > drivers > > > in this case. In my opinion, the fix should be with the touchscreen driver > > > however I did like to have feedback or hear opinions on what is the > > > accepted > > > solution to this. > > > > There is no accepted solution to this yet :( DMA is/was still too rare for > > a serious discussion about this. There is also [1] and probably more... > > > > [1] http://patchwork.ozlabs.org/patch/220137/ > > I believe vast majority of i2c client drivers do not expect that the > transfer buffer they supply in i2c messages are supposed to be DMAable > (unlike USB and SPI buses that had that requirement from the beginning). > > I won't be applying this patch unless we decide that I2C changes the > rules. Understood. Thanks for the clarifications Dmitry and Wolfram. - Sanchayan. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: touchscreen: edt-ft5x06: Prevent DMA driver from mapping an area on stack
On Sat, Dec 12, 2015 at 06:13:55PM +0100, Wolfram Sang wrote: > > > Frankly speaking I do not know where the fix should actually be. I2C IMX > > driver somehow taking care of this or the users of I2C, touchscreen drivers > > in this case. In my opinion, the fix should be with the touchscreen driver > > however I did like to have feedback or hear opinions on what is the accepted > > solution to this. > > There is no accepted solution to this yet :( DMA is/was still too rare for > a serious discussion about this. There is also [1] and probably more... > > [1] http://patchwork.ozlabs.org/patch/220137/ I believe vast majority of i2c client drivers do not expect that the transfer buffer they supply in i2c messages are supposed to be DMAable (unlike USB and SPI buses that had that requirement from the beginning). I won't be applying this patch unless we decide that I2C changes the rules. Thanks. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: touchscreen: edt-ft5x06: Prevent DMA driver from mapping an area on stack
> Frankly speaking I do not know where the fix should actually be. I2C IMX > driver somehow taking care of this or the users of I2C, touchscreen drivers > in this case. In my opinion, the fix should be with the touchscreen driver > however I did like to have feedback or hear opinions on what is the accepted > solution to this. There is no accepted solution to this yet :( DMA is/was still too rare for a serious discussion about this. There is also [1] and probably more... [1] http://patchwork.ozlabs.org/patch/220137/ signature.asc Description: Digital signature
Re: touchscreen: edt-ft5x06: Prevent DMA driver from mapping an area on stack
On Sat, Dec 12, 2015 at 06:13:55PM +0100, Wolfram Sang wrote: > > > Frankly speaking I do not know where the fix should actually be. I2C IMX > > driver somehow taking care of this or the users of I2C, touchscreen drivers > > in this case. In my opinion, the fix should be with the touchscreen driver > > however I did like to have feedback or hear opinions on what is the accepted > > solution to this. > > There is no accepted solution to this yet :( DMA is/was still too rare for > a serious discussion about this. There is also [1] and probably more... > > [1] http://patchwork.ozlabs.org/patch/220137/ I believe vast majority of i2c client drivers do not expect that the transfer buffer they supply in i2c messages are supposed to be DMAable (unlike USB and SPI buses that had that requirement from the beginning). I won't be applying this patch unless we decide that I2C changes the rules. Thanks. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: touchscreen: edt-ft5x06: Prevent DMA driver from mapping an area on stack
> Frankly speaking I do not know where the fix should actually be. I2C IMX > driver somehow taking care of this or the users of I2C, touchscreen drivers > in this case. In my opinion, the fix should be with the touchscreen driver > however I did like to have feedback or hear opinions on what is the accepted > solution to this. There is no accepted solution to this yet :( DMA is/was still too rare for a serious discussion about this. There is also [1] and probably more... [1] http://patchwork.ozlabs.org/patch/220137/ signature.asc Description: Digital signature
