From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Date: Mon, 06 Oct 2014 05:59:15 +0000 Subject: Re: [PATCH] serial: sh-sci: submit rx dma the way the DMA driver can handle it Message-Id: <20141006055914.GA1266@katana> MIME-Version: 1 Content-Type: multipart/mixed; boundary="5vNYLRcllDrimb99" List-Id: References: <1412266448-20266-1-git-send-email-wsa@the-dreams.de> In-Reply-To: <1412266448-20266-1-git-send-email-wsa@the-dreams.de> To: linux-sh@vger.kernel.org --5vNYLRcllDrimb99 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Oct 06, 2014 at 10:55:40AM +0900, Simon Horman wrote: > On Thu, Oct 02, 2014 at 06:14:08PM +0200, Wolfram Sang wrote: > > From: Wolfram Sang > >=20 > > The shdmac driver has a problem when one wants to submit two RX > > descriptors and then use issue_pending on both (like this driver does): > >=20 > > Submit first desc > > -> channel state after: SHDMA_PM_ESTABLISHED > >=20 > > Submit second desc > > -> channel state after: SHDMA_PM_PENDING > >=20 > > PENDING here means: "Oh, we will wait until the first desc is finished > > and then the second desc will be grabbed from the list anyhow" > >=20 > > However, because issue_pending does nothing for states !=3D > > SHDMA_PM_ESTABLISHED, nothing ever gets active :( > >=20 > > Since the DMA driver is probably replaced soon anyhow, I decided for the > > least intrusive workaround which is to use issue_pending on every RX > > desc. (Yes, setting s->active_rx twice is ugly). > >=20 > > Probably not for upstream! However, this patch restores DMA capability > > for SCIFA on my Lager board. Sadly, not for SCIF due to interrupt > > problems still to be investigated. > >=20 > > Signed-off-by: Wolfram Sang >=20 > Acked-by: Simon Horman >=20 > sh-sci patches usually go via linux-serial@vger.kernel.org and > Greg Kroah-Hartman . Could you repost this pa= tch > with those parties included? I wanted to send this patch as RFC, but forgot to rename it :) I'd really like some discussion about it, probably in D=C3=BCsseldorf even. I am still not sure this patch should go upstream, but we should talk about it. Thanks, Wolfram --5vNYLRcllDrimb99 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJUMi+yAAoJEBQN5MwUoCm2TFUQAIZfTK/wf57SB4whfRfVoXm4 6h99ay3XzPiJYg6DiEmNx7t8bHyfYG0bPNNOKnNxRyn6jJu8yaLNUnEcN0Z1i4tS 3XOE3Lv0UtJkE8Wsu/MrAGDIjFHv1B2A9FYCfKfPLaZYcHL/j2mLuOd8OPBU64dW 2zuk4st9+ElkmpZ1rJkqUG6qlNibjRu/xbO774U2UAWN+81t2KPZMT7Eg+5g6MZj qSJ6x4mMnshu2BTEdSsGIKTPWhGyfLuURoQrld1Ry/AT/ACbv6MpbA35E9BXq0eC TDCUBfboGRYkvb2us1tIzDqzi8NNZvvrgWNkQzXCLS+J6nWy/dUkTFY72Mjp5gbV /YwwjqE8DZ4oHk43KZj8/uZOqchKI58OrarBxAk7vEg/fUiLixrBqV9KY4QTcBTB 4o8LgGveQjwss3Ji7TPPN+9g0uOaLYaJRMlcyrdZ/Iu7DXQ3vf4BgcKe7F7xW2g5 kftFOPTxZ53hNFBgnAnIlg8USx9NB055EhxOFmfbNJLxDQ9KWu1q0izVrvV6saZO qWvtU42wc2vWDbMgBoinPcZYruBlI8UMIQk8CbwqnzKk+xoiZBNQBd/scofsQYg6 JUaxPPtsFX3suVv4ccXLK5OJQ87AhJUiFy9P/ekg+zrofL8RhxkdfvDZ41E5RP0x uBdvWas/nHbtjWRHXsxD =9M5T -----END PGP SIGNATURE----- --5vNYLRcllDrimb99--