From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [PATCH] drm: mediatek: remove IOMMU_DMA select Date: Thu, 12 May 2016 10:24:02 +0100 Message-ID: <57344BB2.8020608@arm.com> References: <1462982509-342936-1-git-send-email-arnd@arndb.de> <1462997501-982363-1-git-send-email-arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; Format="flowed" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <1462997501-982363-1-git-send-email-arnd@arndb.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Arnd Bergmann , airlied@redhat.com, David Airlie Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Mao Huang , linux-mediatek@lists.infradead.org, YT Shen , linux-arm-kernel@lists.infradead.org, Matthias Brugger List-Id: linux-mediatek@lists.infradead.org T24gMTEvMDUvMTYgMjE6MTEsIEFybmQgQmVyZ21hbm4gd3JvdGU6Cj4gV2UgZ2V0IGEgaGFybWxl c3MgYnVpbGQgd2FybmluZyB3aGVuIHRyeWluZyB0byB1c2UgdGhlIG1lZGlhdGVrCj4gRFJNIGRy aXZlciB3aXRoIElPTU1VIHN1cHBvcnQgZGlzYWJsZWQ6Cj4KPiB3YXJuaW5nOiAoRFJNX01FRElB VEVLKSBzZWxlY3RzIElPTU1VX0RNQSB3aGljaCBoYXMgdW5tZXQgZGlyZWN0IGRlcGVuZGVuY2ll cyAoSU9NTVVfU1VQUE9SVCkKPgo+IEhvd2V2ZXIsIHRoZSBJT01NVV9ETUEgc3ltYm9sIGlzIG5v dCBtZWFudCB0byBiZSB1c2VkIGJ5IGRyaXZlcnMKPiBhdCBhbGwsIGFuZCB0aGlzIGRyaXZlciBk b2Vzbid0IHNlZW0gdG8gaGF2ZSBhIHN0cmljdCBkZXBlbmRlbmN5Cj4gb24gaXQgb3RoZXIgdGhh biB1c2luZyB0aGUgbWVkaWF0ZWsgSU9NTVUgZHJpdmVyIHRoYXQgZG9lcy4KPgo+IFNpbmNlIHdl IGFsc28gd2FudCB0byBiZSBhYmxlIHRvIGRvIGNvbXBpbGUgdGVzdHMgd2l0aCB0aGUKPiBkcml2 ZXIgb24gb3RoZXIgcGxhdGZvcm1zLCB0aGUgSU9NTVVfRE1BIHN5bWJvbCBzaG91bGQgbm90Cj4g YmUgc2VsZWN0ZWQgaGVyZS4KPgo+IFNpZ25lZC1vZmYtYnk6IEFybmQgQmVyZ21hbm4gPGFybmRA YXJuZGIuZGU+Cj4gLS0tCj4gSWYgc29tZW9uZSBoYXMgYSBiZXR0ZXIgZXhwbGFuYXRpb24gYWJv dXQgd2h5IHRoZSAnc2VsZWN0JyBpcyBoZXJlLAo+IGxldCBtZSBrbm93LCBpdCBjZXJ0YWlubHkg c2VlbXMgb3V0IG9mIHBsYWNlLgoKQWNrIC0gaXQncyBuZWl0aGVyIGFuIElPTU1VIGRyaXZlciBu b3IgYSBETUEgQVBJIGltcGxlbWVudGF0aW9uLCBzbyBpdCAKaGFzIG5vIGJ1c2luZXNzIHdpdGgg SU9NTVVfRE1BLiBJZiB0aGVyZSdzIGFuIElPTU1VIGRlcGVuZGVuY3kgaW4gCmdlbmVyYWwgaXQg c2hvdWxkIGJlIG9uIE1US19JT01NVSwgbm90IHVuZGVybHlpbmcgaW1wbGVtZW50YXRpb24gZGV0 YWlscy4KClJvYmluLgoKPiAgIGRyaXZlcnMvZ3B1L2RybS9tZWRpYXRlay9LY29uZmlnIHwgMSAt Cj4gICAxIGZpbGUgY2hhbmdlZCwgMSBkZWxldGlvbigtKQo+Cj4gZGlmZiAtLWdpdCBhL2RyaXZl cnMvZ3B1L2RybS9tZWRpYXRlay9LY29uZmlnIGIvZHJpdmVycy9ncHUvZHJtL21lZGlhdGVrL0tj b25maWcKPiBpbmRleCAwYzA2YTY5ZDdmMDQuLjU0NTk3M2Y2Yjc0MyAxMDA2NDQKPiAtLS0gYS9k cml2ZXJzL2dwdS9kcm0vbWVkaWF0ZWsvS2NvbmZpZwo+ICsrKyBiL2RyaXZlcnMvZ3B1L2RybS9t ZWRpYXRlay9LY29uZmlnCj4gQEAgLTcsNyArNyw2IEBAIGNvbmZpZyBEUk1fTUVESUFURUsKPiAg IAlzZWxlY3QgRFJNX0tNU19IRUxQRVIKPiAgIAlzZWxlY3QgRFJNX01JUElfRFNJCj4gICAJc2Vs ZWN0IERSTV9QQU5FTAo+IC0Jc2VsZWN0IElPTU1VX0RNQQo+ICAgCXNlbGVjdCBNRU1PUlkKPiAg IAlzZWxlY3QgTVRLX1NNSQo+ICAgCWhlbHAKPgoKX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVsIG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlz dHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlzdHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4v bGlzdGluZm8vZHJpLWRldmVsCg== From mboxrd@z Thu Jan 1 00:00:00 1970 From: robin.murphy@arm.com (Robin Murphy) Date: Thu, 12 May 2016 10:24:02 +0100 Subject: [PATCH] drm: mediatek: remove IOMMU_DMA select In-Reply-To: <1462997501-982363-1-git-send-email-arnd@arndb.de> References: <1462982509-342936-1-git-send-email-arnd@arndb.de> <1462997501-982363-1-git-send-email-arnd@arndb.de> Message-ID: <57344BB2.8020608@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 11/05/16 21:11, Arnd Bergmann wrote: > We get a harmless build warning when trying to use the mediatek > DRM driver with IOMMU support disabled: > > warning: (DRM_MEDIATEK) selects IOMMU_DMA which has unmet direct dependencies (IOMMU_SUPPORT) > > However, the IOMMU_DMA symbol is not meant to be used by drivers > at all, and this driver doesn't seem to have a strict dependency > on it other than using the mediatek IOMMU driver that does. > > Since we also want to be able to do compile tests with the > driver on other platforms, the IOMMU_DMA symbol should not > be selected here. > > Signed-off-by: Arnd Bergmann > --- > If someone has a better explanation about why the 'select' is here, > let me know, it certainly seems out of place. Ack - it's neither an IOMMU driver nor a DMA API implementation, so it has no business with IOMMU_DMA. If there's an IOMMU dependency in general it should be on MTK_IOMMU, not underlying implementation details. Robin. > drivers/gpu/drm/mediatek/Kconfig | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/gpu/drm/mediatek/Kconfig b/drivers/gpu/drm/mediatek/Kconfig > index 0c06a69d7f04..545973f6b743 100644 > --- a/drivers/gpu/drm/mediatek/Kconfig > +++ b/drivers/gpu/drm/mediatek/Kconfig > @@ -7,7 +7,6 @@ config DRM_MEDIATEK > select DRM_KMS_HELPER > select DRM_MIPI_DSI > select DRM_PANEL > - select IOMMU_DMA > select MEMORY > select MTK_SMI > help > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752734AbcELJYI (ORCPT ); Thu, 12 May 2016 05:24:08 -0400 Received: from foss.arm.com ([217.140.101.70]:57077 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752341AbcELJYG (ORCPT ); Thu, 12 May 2016 05:24:06 -0400 Subject: Re: [PATCH] drm: mediatek: remove IOMMU_DMA select To: Arnd Bergmann , airlied@redhat.com, David Airlie References: <1462982509-342936-1-git-send-email-arnd@arndb.de> <1462997501-982363-1-git-send-email-arnd@arndb.de> Cc: Bibby Hsieh , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Mao Huang , YT Shen , CK Hu , linux-mediatek@lists.infradead.org, Philipp Zabel , Matthias Brugger , linux-arm-kernel@lists.infradead.org From: Robin Murphy Message-ID: <57344BB2.8020608@arm.com> Date: Thu, 12 May 2016 10:24:02 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <1462997501-982363-1-git-send-email-arnd@arndb.de> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/05/16 21:11, Arnd Bergmann wrote: > We get a harmless build warning when trying to use the mediatek > DRM driver with IOMMU support disabled: > > warning: (DRM_MEDIATEK) selects IOMMU_DMA which has unmet direct dependencies (IOMMU_SUPPORT) > > However, the IOMMU_DMA symbol is not meant to be used by drivers > at all, and this driver doesn't seem to have a strict dependency > on it other than using the mediatek IOMMU driver that does. > > Since we also want to be able to do compile tests with the > driver on other platforms, the IOMMU_DMA symbol should not > be selected here. > > Signed-off-by: Arnd Bergmann > --- > If someone has a better explanation about why the 'select' is here, > let me know, it certainly seems out of place. Ack - it's neither an IOMMU driver nor a DMA API implementation, so it has no business with IOMMU_DMA. If there's an IOMMU dependency in general it should be on MTK_IOMMU, not underlying implementation details. Robin. > drivers/gpu/drm/mediatek/Kconfig | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/gpu/drm/mediatek/Kconfig b/drivers/gpu/drm/mediatek/Kconfig > index 0c06a69d7f04..545973f6b743 100644 > --- a/drivers/gpu/drm/mediatek/Kconfig > +++ b/drivers/gpu/drm/mediatek/Kconfig > @@ -7,7 +7,6 @@ config DRM_MEDIATEK > select DRM_KMS_HELPER > select DRM_MIPI_DSI > select DRM_PANEL > - select IOMMU_DMA > select MEMORY > select MTK_SMI > help >