Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-04-10 Thread Peter Ujfalusi
Hi Laurent, On 2018-04-04 00:11, Laurent Pinchart wrote: >> +static int dmm_dma_copy(struct dmm *dmm, dma_addr_t src, dma_addr_t dst) >> +{ >> +struct dma_device *dma_dev = dmm->wa_dma_chan->device; >> +struct dma_async_tx_descriptor *tx; >> +enum dma_status status; >> +

Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-04-04 Thread Laurent Pinchart
Hi Tomi, On Wednesday, 4 April 2018 13:33:02 EEST Tomi Valkeinen wrote: > On 04/04/18 13:28, Laurent Pinchart wrote: > > On Wednesday, 4 April 2018 13:02:04 EEST Tomi Valkeinen wrote: > >> On 04/04/18 12:51, Laurent Pinchart wrote: > >>> On Wednesday, 4 April 2018 10:37:05 EEST Tomi Valkeinen

Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-04-04 Thread Laurent Pinchart
Hi Tomi, On Wednesday, 4 April 2018 13:50:43 EEST Tomi Valkeinen wrote: > On 04/04/18 00:11, Laurent Pinchart wrote: > >> + dma_async_issue_pending(dmm->wa_dma_chan); > >> + status = dma_sync_wait(dmm->wa_dma_chan, cookie); > > > > dma_sync_wait() has a 5s timeout. You're calling this function

Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-04-04 Thread Tomi Valkeinen
On 04/04/18 00:11, Laurent Pinchart wrote: >> +dma_async_issue_pending(dmm->wa_dma_chan); >> +status = dma_sync_wait(dmm->wa_dma_chan, cookie); > > dma_sync_wait() has a 5s timeout. You're calling this function with a > spinlock > held. The end result might be slightly better than a

Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-04-04 Thread Tomi Valkeinen
On 04/04/18 13:28, Laurent Pinchart wrote: > Hi Tomi, > > On Wednesday, 4 April 2018 13:02:04 EEST Tomi Valkeinen wrote: >> On 04/04/18 12:51, Laurent Pinchart wrote: >>> On Wednesday, 4 April 2018 10:37:05 EEST Tomi Valkeinen wrote: On 04/04/18 00:11, Laurent Pinchart wrote: > I assume

Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-04-04 Thread Laurent Pinchart
Hi Tomi, On Wednesday, 4 April 2018 13:02:04 EEST Tomi Valkeinen wrote: > On 04/04/18 12:51, Laurent Pinchart wrote: > > On Wednesday, 4 April 2018 10:37:05 EEST Tomi Valkeinen wrote: > >> On 04/04/18 00:11, Laurent Pinchart wrote: > >>> I assume access to DMM-mapped buffers to be way more

Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-04-04 Thread Tomi Valkeinen
On 04/04/18 12:51, Laurent Pinchart wrote: > Hi Tomi, > > On Wednesday, 4 April 2018 10:37:05 EEST Tomi Valkeinen wrote: >> On 04/04/18 00:11, Laurent Pinchart wrote: >>> I assume access to DMM-mapped buffers to be way more frequent than access >>> to the DMM registers. If that's the case, this

Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-04-04 Thread Laurent Pinchart
Hi Tomi, On Wednesday, 4 April 2018 10:37:05 EEST Tomi Valkeinen wrote: > On 04/04/18 00:11, Laurent Pinchart wrote: > > I assume access to DMM-mapped buffers to be way more frequent than access > > to the DMM registers. If that's the case, this partial workaround should > > only slightly lower

Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-04-04 Thread Tomi Valkeinen
On 04/04/18 00:11, Laurent Pinchart wrote: > I assume access to DMM-mapped buffers to be way more frequent than access to > the DMM registers. If that's the case, this partial workaround should only > slightly lower the probability of system lock-up. Do you have plans to > implement a

Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-04-03 Thread Laurent Pinchart
Hi Peter, Thank you for the patch. On Thursday, 22 March 2018 15:42:06 EEST Peter Ujfalusi wrote: > From: Tomi Valkeinen > > Errata i878 says that MPU should not be used to access RAM and DMM at > the same time. As it's not possible to prevent MPU accessing RAM, we >

Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-03-29 Thread Peter Ujfalusi
On 2018-03-29 13:18, Tomi Valkeinen wrote: > On 22/03/18 15:42, Peter Ujfalusi wrote: >> From: Tomi Valkeinen >> >> Errata i878 says that MPU should not be used to access RAM and DMM at >> the same time. As it's not possible to prevent MPU accessing RAM, we >> need to

Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-03-29 Thread Tomi Valkeinen
On 22/03/18 15:42, Peter Ujfalusi wrote: > From: Tomi Valkeinen > > Errata i878 says that MPU should not be used to access RAM and DMM at > the same time. As it's not possible to prevent MPU accessing RAM, we > need to access DMM via a proxy. > > This patch changes DMM

Re: [PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-03-23 Thread Peter Ujfalusi
On 2018-03-22 15:42, Peter Ujfalusi wrote: > From: Tomi Valkeinen > > Errata i878 says that MPU should not be used to access RAM and DMM at > the same time. As it's not possible to prevent MPU accessing RAM, we > need to access DMM via a proxy. > > This patch changes

[PATCH v2 2/2] drm/omap: partial workaround for DRA7xx DMM errata i878

2018-03-22 Thread Peter Ujfalusi
From: Tomi Valkeinen Errata i878 says that MPU should not be used to access RAM and DMM at the same time. As it's not possible to prevent MPU accessing RAM, we need to access DMM via a proxy. This patch changes DMM driver to access DMM registers via sDMA. Instead of doing